UC BERKELEY MASTER NEGATIVE STORAGE NUMBER 03-67.73 (National version of master negative storage number: CU SN03067.73) MICROFILMED 2003 UNIVERSITY OF CALIFORNIA AT BERKELEY LIBRARY PHOTOGRAPHIC SERVICE REPRODUCTION AVAILABLE THROUGH INTERLIBRARY LOAN OFFICE MAIN LIBRARY UNIVERSITY OF CALIFORNIA BERKELEY, CA 94720-6000 COPYRIGHT The copyright law of the United States (Title 17, United States Code) governs the making of photocopies or other reproductions of copyrighted materials including foreign works under certain conditions. In addition, the United States extends protection to foreign works by means of various international conventions, bilateral agreements, and proclamations. Under certain conditions specified in the law, libraries and archives are authorized to furnish a photocopy or other reproduction. 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Geological report of Meadow Valley and vicinity 1913 BIBLIOGRAPHIC RECORD TARGET University of California at Berkeley Library Master negative storage number: 03-67.73 (national version of the master negative storage number: CU SN03067.73) GLADIS NUMBER: 184783749B FORMAT : BK AD:991004/FZB LEVEL:D BLT:am DCF:a CSC:d MOD: EL:7 UD: 000201 /FVB CP:cau L:eng INT: GPC: BIO: FIC: CON: ARCV: PC:s PD:1913/ REP: CPI: FSI: ILC: T1:1 040 CUScCU 090 SbDISS.CLAUSEN.GEOL 1913 100 1 Clausen, Ervin H. 245 10 Geological report of Meadow Valley and vicinity. 260 $c1913. 300 iii, 54 leaves :8bill., col. maps ;$c29 cm. 500 Includes index. 502 Thesis (B.S. IN Geology) --University of California, Berkeley, April, 1913. 504 Includes bibliographical references. 610 20 University of California, Berkeley.SbDept. of Geology and Geophysics$xDissertations. 690 0 Dissertations, AcademicS$SxXUCBSxGeologySy1911-1920. Microfilmed by University of California Library Photographic Service, Berkeley, CA FILMED AND PROCESSED BY LIBRARY PHOTOGRAPHIC SERVICE, UNIVERSITY OF CALIFORNIA, BERKELEY, 94720 DATE: 08/03 REDUCTION: 10 X Thesis for B. 8S. Degrees. Geological Report of Meadow Valley and Vieinity. * CLAUSEN E. H. ad ERP OSIEAPH E.H.Clausen Meadow Valley Plumas Co. tock (cflcTiery GEOLOGICAL REPORT of MEADOW VALLEY AND VICINITY. by E.H.CLAUSEN. '13. GEOLOGICAL REPORT OF MEADOW VALLEY AND VICINITY. 3 ssessceJNDEX cevcese Subject. Page. Letter of Transmission ecccccccsccecccscssssscscscssssacsscscsscsnsssnces Description and Interpretation of Land FOG as essssssensetdsessssnsnsecsthe LOCRLIOR ss asvsssssstsssssssnsssssonsssssssenssstasssssenssssvsnnsle MepPSeseceeessscscstsosssasesosnssscsssssosssnssscsesessscsssscsssnsle TOPOEraPhY ee eesesscseascsscssssssesssassesssssesssscsnsssssssanenede GEOLOGY AND PETROCRAPHY. Comparison with Previous Work saves ssessssesssssssssssnsscovassnsssnsenede Bed=Reck COMPLEX esoseesssssssstessnsscnassccsasssasssassssssassasssccsesde Celaveras FOrMAtiON coonsessssssssssstsasssssnesssevsrsasnsessssssnesvesifie CONLEACED « co 00sensssnsssasssnsssvinsssssssssssssssnsssasnsssenseensdOs 3chistosity and Bedding eesessessssscsscscseascssecansasanssaasessille S18EGEB es asssssretassrssnssssrssssssntssavesvestsensaesansnssneesnlBe MetemorphislMeseeecesssssscscscccssasessasscacssscssasccssssocensclle Phyllite and Quartz=Mica 3chistEessacenstcessssssssvsssstnnessscalde LiMBAt ONG es sstesstsssssscasssssetssssssossssansnsnssssssnscsseneslBe Amphiboliteceeesecsosesoscvacrvssensssscescssceascsscccsssscscssssscsnsesslle Diadem LBB as ssesssscnscssssntssnsscesssssncasssesssstsscansesssnnesesiBe Fossils of the Diadem L d@cceccesceccsscscenrcsssscenscssscsasesdlBe Faulting and Metemorphism of the Diadem Lod@secccsccscssccssccendlBe Rocks and Minerals of the Diadem LOdSececssesssssssescssssscsceaalle OUtCrOPSscsescscssesssscssscsscsvsosssssssssassscsnsssscsssasesche24, Greenstone FOrmationecssssssssssssssssanssscssssrsssssnsssssscssssnssandi, Origin of the GresnatOngcsssssvesssssrsssssssssssstscsstssnnsseeebe Purple Greenstone Schistteassessenssscsssnsssstasessssssssnssssnadle Gneissoid Amphibolit@eceesecesscsensesscacctccssnssenssscanssncssccsscaese 3erpentin@ccscessscsesssesssccscssccccassesscsssesessccsscascssccssceelBe CP ANI AGE cesar noite stsrttssrsostssansssssesstssssessssnessnnssnssnanss2Ve Border ROBB rec cs srs are rr esis tsessrussss ite sesnssinsiees assists Gneissoid SErUCEUrG ee ssserssssssssssssssestsvesnssnsssssssssansnnsie Partings and JOitts esse crannstrrrsassstsssesnssssrnssssssncssvssdne DI RBG esc vssssacnesssnssstorssssssessssessssnnsescnsssssnansssssancde Super jacent SOP I0B ccissesssrisrssssssstsersssensnrnsenessnvsssnssensside GEOLOGICAL REPORT OF MEADOW VALLEY AND VICINITY. eeveeeeJNDEXcceoeee Subject . Page. Tertiary PoFiOfcicsnssvitvesssavensasssnsscstsassssnsneivasasnevevessdDe Auriferous River GraveliesisscscstscsssssssssssssnscssssnsnsenesndBe Older 3YStOMeccssssrssacasanssssassesnsassssnsasssnssnscsssasssesdle Younger 3VStEMeccssesssssscsssasssnssasssarsascsascnsssscsasasensdle Leke Gravels of Meadow ValleYessoessassssscssssseasasssnscsssnsaccscesdde Volcanic ROCKS «csssesnsssssssesssssunsnsnssssnsssssssnvssnneenssesnsesnils Andesitic BroCCiai. sessssesssssssasssssssssssssasasevevancessnnnstle BHSEIt oc sscssnsssstesessssssssvasessasnssennsastevansnsnsnnsennnidde CLBELEtion esses tssssnnsserssssrestssinsssnssesssnnssssnavansnnnravandde FOUN csessvsssseseasssssrssssssssnenssannnnsvernssssennneavennnereile SUBIMBEY ++ «resssrsssssssrssnssssssrsssssscsesnsnersssssnnsseennsseneensll, AAAAAAAAAAA “°° AAAAAAAAAAA Berkeley, California, April 13th., 1913. Professor Geo. D. Louderback, Ph.D. University of California, Berkeley, California. Dear 3ir,: I have the honor to submit to you, for my thesis, a "Geological Report of Meadow Valley and Vicinity" and especially with reference to the Diadem Mine. The work embraces the geology and petrography of the area mapped and represents one month of field work and such office work as was necessary, and such time as could be spared during my Senior year at the University of California. Respectfully submitted, 1. GEOLOGICAL REPORT OF MEADOW VALLEY AND VICINITY AND ESPECIALLY WITH REFERENCE TO THE DIADEM MINE. 8200800000 DESCRIPTION AND INTERPRETATION OF LAND FORMS. LOCATION. The area mapped is Msadow Valley and vicinity, in the county of Plumes , 3tate of California; and while having no special designation as a mining district, it can readily be located. It covers an area of about twenty-four square wiles in the northeast corner of the Bidwell Bar Quadrangle of the United 3tates Geological 3urvey, and in particuler; part or all of sections 10, 11, 14, 15, 21, 22, 23, 26, 27, 28, 29, 30, 31, 32, 33, 34, and 35, in Township 24 North, Rene 8 East, and sections 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15, 16, 17, and 18, in Township 23 North, Range 8 East, Mount Diablo Meridian and Base Line. Tn the early days of plecer mining in California, this locality known more widely as 3panish Ranch was very prosperous; placer gold being found in the valley bottoms and in most all of the streams that drain Spanish Peak. Thirteen miles East is the town of Quincy, the county seat and now, mostly a tourist resort . The population averages about five hundred. Spanish Ranch and Meadow Valley together have a population of about one hundred people. The Oroville=Quincy county road runs thru this section, and before the operation of the Western Pacific railroad in the Feather River Canyon was the only means of travel between Oroville, Quincy, Greenville Tavicrevills and the Honey Lake region. 2. As before stated the area mapped has no designation as a mining district, however, a smaller section, near Edmanton was known as the Eagle Gulch mining district, and was the richest placer ground in the neighborhood. In order to more fully illustrate this report, a topographical map with a scale of 1,000 feet to the inch, shows the distribution of the areal geology, and represents one month's continuous work in the field , during the summer of 1912. Two and one-half months was spent in this district, the first month and a half being devoted to work at the Diadem mine, all spare time being used in getting thoroughly acquainted with the ground « It was through the courtesy and kindness of Mr. Wm. Watson, EM. fomerly chief assistant to J.B Mills, that I was able to procure and trace from the original surveys, the topography of the area. I take this occasion to thank Mr. Watson for his kindness. Besides the areal map, six cross=sections were made to show the structural relations. Maps of Plumas county and the 3tate of California are also included to give the reader an exact idea of the location of the ground. The smaller maps of the Diadem mine and vicinity and a cross= section of the Diadem beds according to J.A.Edman is included in the report, in order to represent some special features of the geology about Edmanton. As the workings of the Diadem mine were closed, a check could not be obtained upon the cross-section of the Diadem beds. According to J .A.Edman a bed of slate is between his so called aphanitic diorite and amphibolite. This was not noticeable on the surface. Neither was any lower Diadem bed noticeable. The only surface indication is the lens of amphibolite. The cross~saction by J.A. Edman is included, as this is supposedly drawn as mining operations progressed od and is the only obtainable section of the lode . 3. Where necessary, photographs are included te fully illustrate the structural geology. TOPOGRAPHY . The topography is chacteristic of the western slopes of the 3ierra Nevada mountains, and within these twenty=four square miles, is found valley, hill, and mountain land, varying in altitude from 3600 to 7,000 feet above sea level. HILLS AND MOUNTAINS. - 7.3.Diller in his " Notes of the Geology of Northern California” divides the 3ierras into three blocks, namely,- western, middle, and eastern. The Meadow Valley region is classed as belonging to the sastern edge of the western block; the land being in general, high and stesp hills, with the glacial scarred and ragged sides of Spanish Peak, rising on the West abrubtly; 3,000 feet above the valley. S00 00 sO BEN spanish Peak, looking west from Spanish Ranch. 3panish Creeak and the old Meadow Valley lake bed in the foreground. RETAKE OF PRECEDING FRAME r om Em From the promontory of 3panish Peak the larger land forms show little relief, and seem to grade off slowly and evenly toward the Middle Fork of the Feather river , to the southwest; and toward Quincy to whe east. To the | north the land drops to the lsvel of the valley in easy stages. The noticeable feature is the eveness of the high points, which seems to have a gentle slope to the southwest and toward the 3acramento valley. In contrast to this relief , when one decends into the hills they are found to be rough, exceedingly steep and coverd with a network of ravines, gullies and canyons that would soon cause the unacquainted traveler to lose his way. The most characteristic feature is the decided and sharp V shaped gulches. These two features,- the even rolling topography of the high points and the sharp V shaped gulches of these larger divisions, clearly indicate two distinct periods of erosion. The first belongs to the Tertiary and the latter to the post=tertiary or Pleistocene periéd. SURFACE; VEGETATION AND TIMBER. The surface is densely timbered and contains in places a dense underbrush. It is noticeable that the timber confines itself to the Bed=rock Complex mostly. The rounded high hills of.andesitic breccia and granite are s0 densely covered with a short thick manzinita and "buck" brush as to make them almost impassable. The numberless, stecp and bushy gullies and the dense brush covered hills makes the tracing of contacts slow and difficult. The timber is the valuable asset of the region , and a most excellent growth of sugar-pine, California white=pine, spruce fir, cedar and * tamarack is protected by the National government. The timber grows right into the valley. Most all of the open agricultural lands have bean clesred of brush and timber making good grain land. No orchards are cultivated in the valley, but at the Todl-Gate at a higher altitude excellent apples are grown. Se In sharp contrast to this timbered area the steep and glacial sgarred sides of 3panish Peak are either bare of all vegetation or covered with a dense brush. SPs DOeBeBHLLE Spanish Peak looking northwest from 3cad Point. 4 : ! ¥ { B i i k b 4 i The 3cad Point channel is in the foreground and the Clear Creek Cirque in the background. Left Branch of Big Creek, locking northwest toward Spanish Peak and showing vegetation and gentle slope of the larger land forms. ANVIL ONIAIDTAd AO IIV.LAA STREAMS AND WATER SUPPLY. The trend of the ridges have a marked Bearing on the drainage. While having a gentle slope to the southwest, in general, the heterogeneous character of the rocks and the dislocations which they have been subjected to have produced greater irregularity than is the case in other parts of the range. In the eastern part of the county the ridges have a decided north west and southeast trend, but at Meadow Valley therecis no continuous range. One mile south of Edmanton is the watershed of the North and ’ Middle Forks of the Feather river. The canyons are so circuitous and deceiving <. . that th watershed is difficult to follow. Bear Creek on the south, flows into the Middle Fork of the Feather river, while Buck's Creek flowing to the southwest drains into the North Fork of the Feather river. Most of the land is however drained by 3panish creek which flows east, then north and finally by describing a complete circle discharges in to the North Fork of the Feather river. ‘The water supply is very abundant, every gully containing some water that erodes the V shaped channels rapidly. This supply is of great advantage to the placer miner who can work his ground to the middle of July. Theabundance of water is the cause of the dense growth of vegeta- tion. As soon as the snow leaves the ground in May the young plants grow rapidly, so that in three months a rank grewth of vegetation spreads over the ground hiding all the small features. a i TH, . } X i Office, Diedem Mine, Edmanton, Plumas County, Califcrnia. El ! } 8 3aw Mill, Diadem Mine, Edmanten, Plumas County, California. i GENERAL GEOLOGY including PETROGRAPHY . GENERAL GEOLOGY AND PETROGRAPHY . COMPARISON WITH PREVIOU3 WORK. In 1898 .H.W.Turner mepped the Bidwell Bar (uadrangle, but as the time spent was necessarily shert, winy minor features were left unmapped. Meadow Valley being in the ncrtheast cerner of the quadrangle was mapped at this time. In mapping the geclogy for this report, the United States Geological. Survey Folio was not referred to, but was compared with on completion. The larger formations such as the granites, slates and serpentines checked, but considerable variation was found in the minor details, none or few, being mapped in Turner's report. It will noted that no lens of amphibolite is mapped at Edmanton nor is any division made of the lake gravels of Meadow Valley. The greatest difference however is noted at the western contact of the serpentine where the survey has mapped two amphibolite lenses in the Calaveras slates. This was found to be erroneous. It is possible that a slaty to purple schistose greenstone was mapped as the Calaveras formation. BED=ROCK COMPLEX. The North Fork of the Feather River is practically ks the northern limit of the 3ierra Nevada Mountains, for north of this river the bed-rock complex is covered by the lava flows from Lassen Peak, while to the scuth are the typicel 3ierra Nevada formations., that have been divided into the older Bed=rcck complex and the ycunger 3uperjacent series. The Bed=rock complex consists of.sedimentary rocks which were turned into a nearly vertical position during or before the post= juratrias deformation, together with the associated igneous rocks. The sedimentary rocks of this series represent beds of clay, sand and limestone which have been hardened and metamorphosed. These beds were originally horizontal tut have since been folded and greatly compressed hy forces acting in an ENE and W3W direction. The upper parts of the folds have been eroded leaving the upturned edges. Intercalated with these sediments are lenses of metemorphic tuffs and lavas, showing that volcanic action was going on during deposition. Irregulerly intruding these layer of sedimentary and volcanic rocks are dikes and lerge masses of igneous rocks, chiefly, grancdiorite. The strikes and the contacts between the various formations are roughly NNW and 33E and the schistosity and bedding are conformable in most cases. SEDIMENTARY ROCKS. CALAVERAS FORMATION . The Calaveras formation is the only series of sedimentary rocks represented in this section. It consists of clay-slate, phyllite, siligcified slate, quartzose schist, quartz schist, mica schist, and limestone. CONTACTS. The only marked contacts are thése of limestone, greenstone and granite. The contacts between the mica schists, clay-sddte and quartz-schists are indefinite. One rock grades insensibly into the other with morse or less variation, due to metamorphism. 11. The granite contact is well defined and swings in graceful curves from the east base of Spanish Peak in Meadow Valley southernly into Buck's Valley and back over the hill at the head of Big Creek, easternly into Bear Cresk, where it is lost under the andesitic breccia, near the U.3.Bear Creek Forest 3tation. The most peculiar thing noticed in following this contact is the growth of the brush, which seemed to roughly mark the division between the granites and the slates. The brush is more dense in the granite than in the :.u slates. SCHI3TOSITY AND BEDDING. The schistosity and bedding in general correspond. Near the granites are in places greatly contorted. In a good slate specimen from Eagle Gulch, owned by J.A Edman, a difference between the bedding and the schistosity planes of about five degrees was noted. This schistosity roughly follows the main granite mass from Spanish Peak in Meadow Valley southernly to the head of Big Creek. Here the granite contact makes an abrupt change in direction to the East, and an arm or finger of granite extends into Bear Cresk for three miles. The schistosity of the slates is not conformeble with the granite finger, but continues in the same general direction with reference to the mein mass and hence is unconformable with the smaller mess by about thirty or forty degrees. In passing southwest across the schistosity of the formations from the clastic greenstone to the granites , the following variations are gen=- erally noted , = Clastic greenstone | Indefinite contact of slate and tuffacecus material. Clay slate. i 3ilicified slate. Quartz schist. ] Limestone (Diadem Lode) | Amphibelite « ] Quartz schist and silicified slate 1 ( Clay slate. ! Phyllite. Mica schist. J Granite. i 12, In examining the above facts it is clear that the slates were affected by two factors, either separate or together; namely,- schistosity due to great dynamic action and veination due to circulating waters. That the greater part of the schistosity is due to one intense mountain making movement seems probable. The deposition of the silica is caused by waters that found geod circulation along the shear zones resulting from the 3panish Peak uplift. As originally laid down, the sletes show by their extremely fine grain, eveness of texture and black cclor that the original sediments were very fine and deposited in still water of a more or less moderate depth. That clay was also present is established by the strong kaolin odor. The black color is probably due to carbonaceous material. What the thickness of this bed was, is hard to say, for the intense compression due to the folding and the loss due to the granitic intrusion, makes a calculation worthless. The exposed surface shows it to be no less than 4,000 feet, if no folds are taken into consideration. Considerable time was spent in trying to work out the folds, but after taking some fifty dips and strikes, it was found to be useless. The slates were vertical or nearly so and the steep canyon sides caused much surface creep. -ing due to gravity. "hile these sediments were being laid down or during the subsequent folding and compression they were intruded by a lens of massive amphibolite. METAMORPHI 3M . With the intrusion of the granite mass the sediments were subject -ed to a second metamorphism and the phyllite and quartz mica schist were partly dissolved and metamorphosed. The most intense action is at the contact, where the slates are in places cempressed,ptwisted, snd—bhaked, 6 leaving no doubt as to the contact metamerphism. Along the contact the slates are found to vary considerably . Some slates would still show the fine grained structure but twisted and curved in knots, concentric shells and wavy layers. Where the silica bearing waters found good circulaticn lenses of quartz are formed from en inch to as large as ten feet in length, the width being about one tenth of the length. Then again the slates are silicified and hardened to almost form, a quertz schist, that has a most pronounced metallic ring. With the increase of the silica, the color change from a fine grained bleck slate to a light gray silicified and somewhat granular slate. PHYLLITE AND QUARTZ=MICA 3CHISTS. The granitic and amphibelitic intrusions and dynamic netemorphiem have changed all but a small area of slate around Edmanton. The phyllite end quartz-mica schist comprise the greater part of the Calaveras formation, while the true clay=-slate is subordinate. Near the Toll Fate the phyllite is interleminated with quartz schist and crystalline limestone, the latter , however, veing only a two foot bed near the granite contact, and not continuous. On following the slate south these gave way to a quartzemica schist and at the head of Big Creek , no phyllite is to be found, but a coarse grained quartze-mica schist instead. This is the contact rock at this point. In the canyon, however, the phyllite is the prominent rock and continues into Bear Creek. jcattered thru the Calaveras slates at several points are veins of cuartz or zones of silicification that can be followed with the eye for hundreds of vards. These outcrops being more resistant than the balance of the rock stand out in bold relief, and at first appear to be quartz veins or dikes, when seen from the distance. In width they vary from twenty to forty feet and comprise a zone of intense sgilicification, that gives way in places to a true quartz schist. The strike of these veins is parallel to the schistosity. 14. The dir of the slates is 70 to the N.E. and the strike N37 WV. The dip varies so greetly thet a correct determination is hard to obtain . All the rocks of the Bed=reck complex stand nearly on end. 0000000800 5late outcrop one~helf mile west of the Toll Gate on the east flank of 3panish Peak. 2 P 00000000 ~ That the western edge of the slates is the oldest part is assumed by the dip, at apparently good places, and the dip of the Diedem Lode and the vesicular nature of the amphibolite foot-wall of the lode .Refore: the folding of the Calaveras formation was going on, successive layers of tuffs, breccias, and massive lavas were being deposited upon the sediments, all ¢f which were pressed together, metamorphosed and recrystallized. On the left branch of Big Creek alternate layers about one inch wide of quartz schist and tuffaceocus cley sediments is found . The quartz schist is most abundant, end at the head of 3nyder's Creek large outcrops of contorted quartz schist stand in bold relief to the rest of the surface . This suggests that the clay sediment deposition was stopped, and after the depcsition of the 15. Disdem limestone beds, the quartz schist was formed and as conditions again became normal the clay sediments again formed shale beds. In the interval between the deposition of the silica end the clay sediments, alternate lavers of silica and clay was deposited, due perhaps to successive perieds of sedimentation and volcanic activity. As the soft gray layers between the quartz schist shows much silica, it is possible that the silica deposition was still geing on, while the clay sediments were being laid down; the mixture of the two forming a light gray silicious layer. The locel varietion of the formation is interesting, hoth in the effects of metemcrphism and the changes in the rocks. ‘At one point the metamorphism is very marked, the sletes being twisted, hardened and baked to a brownish mess with little slaty appearance left; while at another point the gletes for a great distence from the granite show no variation. The same fine grained silky and lustrious phyllites or gericite-schists can be found near the contact as is found 400 yards away. No twisting or contorting is noticeable. Above the Toll Gate quartz-schist alternates with the slate, while one-half mile south lenses of light gray granular quartz is prominent in the slates. Along Pig Creek the fire sericite schist is predominant, until near the head it suddenly changes to a coarse Quart z-mica schist, the southern edge of which is unconformeble to the Bear Creek granite arm by ebout forty degrees. Along the Pear Creek watershed no centact metemorphism is noticeable end the phyllites lie against the granites uncenformably. Another fact worth mentioning is that where the sletes show a mark -gd metemorphigm, the granites are gneissoid and where the phyllites and coarse quartz mica schists occur the granite are not gneissoid but soft and friable. This fact is sure . The granites have not affected all the slates of the formation alike. A change ig noted at the summit where the Spanish Peak granites become softer and more friehle and change to the non-resistant granites cf Bear Creek. This seems to indicate that there is a variation in the granite mass; for as will be discussed under granites,the rock at the north end of the Peak is harder and more resistant and different from that of the southern end. The question immediately arises. Is the granite mass of one age representing one great intrusion or is an older granite mass present.? LIME STONE . In the slate formation are two beds of limestone; one, one-half mile west of the Toll Gate und fifty feot from the granite contact at the head of Clear Creek, and another, the most important, at Edmanton. The first is a small bed of gray crystalline limestone four feet wide and not con tinuous. The outcrop was found in an extremely dense brush, making close examination impessible. DIADEM LODE. The second bed is the Diadem Lode at Edmanton, consisting of a dolomite bed one-half mile long and forty to sixty feet wide. Along this lode the most interesting geological features of the section occur. In order to describe this lode the lens of amphibolite which forms the foot-wall of the lode will have to be considered at the same time. AMBHIBOLITE . Intruded into the center of the Calaveras formation and following it in strike is a lens of massive green amphibolite, two miles long and averaging 1200 feet in width. The border of this lens is very schistose and oxidized, but in the center on Big Creck and on Mumford Hill it is massive and shows the original minerals. Most all of the outcrops are soft and rusty in color. On the eastern border or foot=wall side of the Diadem Lode, the lens is vesicular; the 17. subsequent compression te which it was sujected elongating the vesicles and meteoric waters filling them with calcite. Pyrite which is lacking in the slates is abundant in the amphibolite and a source of iron. Along the foot-wall pyrite cubes up to one= quarter of an inch are abundant. Besides pyrite an abundance of magnetite in the form of octahedrons is scattered thru the amphibolite near the eastern border of the lens and range in size from microscépic grains of a peppery appearance to crystals one=sighth of an inch in length. The magnetite is most abundant near the calcite and in the flattened vesicles, the small crystals occuring in the schistose amphibolite. Ahove this intrusive sheet the Diadem limestone was laid down, but it is to be noted, the amphibolite is aliacernt to it only at Edmanton . Both north of Eagle Culch and south of Big Creek the limestone is entirely in the quartz=schist. That the amphibolite is the contact rock at Mumford Hill only, is additional proof of its intrusive nature. That it is vesicular only where it is in contact with the Diadem Lode leads to the conclusion that only this part was exposed at the time of its intrusion. Fossils have been found at many places in the lode. The greater part of the fossils in the dolomite have been destroyed by metamorphism. The fossils that are left are silica replacements. The meteoric waters dissolved awav the carbonate and replaced it by silica. The dissolution of | the carbonates decreased the volume by shrinkage;cavities were formed in the limestone and these filled by crystal quartz, which furnished a crystal quartz- breccia when faulting occurred. Under the microscope the massive variety shows an abundance of hornblende and its alteration product chlorite, in all about 75k. No quartz is present but the foldspars which are mostly plagioclase, were much altered and kaolinized. : i | § ¢ ! i 18. FO33IL3 OF THE DIADEM LODE. The fossils were determined by Professor Merriem of the University of California as being a forminifera of Carboniferous age. These are small ovoid bodies up to one-quarter of an inch in diameter with their greatest length parallel to the bedding of the limestone and the schistosity of the Bed=rock complex. FAULTING AND METAMORPHISM OF THE DIADEM LODE. After the intrusion of the amphibolite, deposition of the limestone and subsequent folding; the intrusion of the large granite mass tended to increase the dynamic metamorphism . With the uplift of the Spanish Peak granite, the country was successively step-faulted. One of these faults followed the Diadem Lode . The throw of the fault is small and according to J .A Edman only forty feet. The evidence to support this is the fact that there is no gouge and the resulting breccia has not been crushed enough to destroy the fine specimens of crystal quartz. These quartz crystals are in abundance, showing the extensive work of the meteoric waters which dissolved large cavities in the limestone. In these cavities the quertz crystals were formed. After faulting, a breccia of broken white quartz and small quartz crystals were cemented by a ferruginous clay , derived from the soft foot=wall. In places the cement was silicious, in other places calcareous, and in the Chicken Flat cut, manganese and limonite formed 2 cementing material, that held together a brecciated mass eight feet in width © which occupied the center of the lode. Good specimens were also found where the cementing material was massive red limonite or hematite. The quartz crystals are gmall, clear, and some double=ended. The prism faces showed repeated twinning. This indicates an oscillatory growth. SOP RPDOBS Hydraulic cut at Rig Creek in the Diadem lode, showing foot= wall of amphibolite and dolomite boulders on the left, and a large mass of quart z=breccia, cemented by manganese end limonite,in the foreground. ROCK3 AND MINERALS OF THE DIADEM LODE. The most interesting feature of the Diadem lode is its variety of minerals, both primary and secondary. That the limestone was laid down under water is evident from its fossils and from its structural characters, but the formation of its gold is not so evident. As before stated the meteoric waters had attacked the limestone and when mining exposed the underground structure, large residual boulders of dolomite were found scatterd thru the lode. These boulders contained a black gold selenida, occurring in blotches disseminated thru the mass, and in small stringers or threads showing a rough parallelism. One specimen was found that showed stratification. Interlaminated with the dolomite are bands, layers or lenses of black gold selenide up to one=oighth of en inch thick. 20. Five of these layers are included in two inches of dolemi‘e. This bedding effect is parallel to the strike of the lode and stratification of the slates. 3econdary veins of calcite and quartz in size up to one-half inch and in places larger, divides the dolomite into a network of sections; the mottled gray appearance of the selenide patches being in sharp contrast to the clear white veins. Most of the gold was found in the foot-wall side of the lode, as was also the greater part of the selenide. The bonanza or big pocket of free geld was found at Mumford Hill. This is the only place vhere the limestone and the amphibolite form a good contact. Further prospecting failed to disclose other bonanzas, which seems to indicate that the intrusive lens was a factoe in the deposition of the gold. These facts lead to the conclusion that the selenide was extracted from the sea water at the time of deposition of the limestone, and hence was & part of the lode before faulting tock place. With the faulting it appears that the solutions acting on the dolemite extracted the gold, reduced and precipitated it,along the foot-wall producing secondary mineralization. Copper minetals in the form of malachite and tetrahedrite are found in a small quartz vein near the foot-wall and at the center of the big cut. During the placer cleanrups masses of hematite averaging in size up to a hen's egg were frequently found. These pebbles were rounded and the only hard and undecemposed rocks left in the old channel on Mumford Hill. Associated with the calcite in the vesicles of the amphibolite aléng the foot=-wall of the lode are an abundance of octahedrons of megnatite. In places along the foot-wall and bordering it for a width of twelve feet are an abundance of secondary cubes of pyrite up to three-eights of an inch square. This iron,that is all the iron in the lode , may have one of two sources or perhaps both. The Tertiary lava flows of basalt were extremely rich in iron, every emygdule being lined with hematite besides the great amount of magnetite scattered thru the rock itself. The basalt has almost been eroded eway, and naturally, the contained iron would tend to concentrate. The other source is the amphibolite, which is alsc rich in iren especially pyrite. The ease with which the rock is oxidized sets free the iron, and circulating waters tend to concentrate it. The menganese in the lode ies also secendary end its concentration there is due perhaps to a leaching eof the mangenese depcsits found higher on the ridge and cone mile to the south. Not only is the manganese cxide found in the lcde but also the silicate and the carbonate, that is, rhodonite and rhodochrosite One mile south of Edmanton at the head of the Greenstone Ravine, is an outcrop of manganese in the form of pyrolusite and psilcmelans, a massive dense dull black mineral esscciated with a quartz vein. This deposit has been prospect -ed and disclosed a small two-foot vein in the midst of a striped red tuff, which resembles very closely a rhyclite tuff. The deposit is within fifty feet of the slate-amphibolite contact. The menganese is both hard and also in a soft granuler form, associated with quartz both crystalline and granular. eos ss Basa Manganese outcrop, one mile south of Edmanton. scattered thru the dolomite and the metamorphosed amphibolite at the foot=wall contact are small specks, or grains of a bright green mineral, that resembles very closely the Mariposite of the Mother Lode region. When dissolved in acid and neutralized with sodium hydroxide a characteristic green precipitate of chromium hydroxide formed. The hanging wall of the lode is a quartz=schist of a peculiar pink celor that is due to iron oxide. Blowpipe failed to prove the presence of any manganese . According to J.A Edman this pink hanging=-wall rock is the only indica- tor of the Diadem Lode. On Mumford Hill at the south end of the hydraulic cut the quartz=schist Rangingvall seems to be displaced by a dense fine grained jaspery or cherty rock that forms a horse in the lode. This reddish=brewn iron colored rock which alternates with thin layers of blue shale, one-half inch thick, appears to be bedded cherts, with layers up to two inches in width. Due to metamorphism and strain , the rock under the microscope shows a fine mosaic structure in the quartz, which gives a biaxial figure. In the zone of movement in the Diadem Lode this rock is a recemented breccia, white quartz being the cementing material. This white coler in contrast to the red of the breccia makes & very pretiy ground section. Intense shattering produced anguler fragments, up to one inch in length with an orientation parallel to the schistosity of the bed=rock cannlox. Serrated anhedral quartz with unduletory extinction is noticeable. The rock is colored red by iron oxide and thru the mass is scattered considerable grains of magnetite, in the form of octahedron crystals, but so small as to be hardly distinguishable ex- cept with a high pewer in the sunlight . This reddish rock is mostly quartz and very likely of the same origin as the quartz=schist of the hanging-wall, which is not influenced by the presence of iron. A ground section showed a ribboned structure in the quartz, indicating precipitation from solution. The amphibolite foot-wall is much decomposed changing from its green color to a dirty yellow. At the Arrastra Ravine an exposure of amphibelite shows the normal dip, which is reversed at the lode due to gravity and surface creep. The nonresistability of the lode and gravity caused this reversed dip. S000 0800e0 Big Creek looking west and showing how the waters have cut into the soft and decomposed lode on the south side of Mumford's Hill leaving a small flat of about two acres and the only widening of its V shaped channel in six miles. sec es BOan Traversing the foot=wall rock near the lode are several two-inch veins of quartz carrying a large percentage of tourmaline, both massive and in needle crystals. Other veins contain much chlorite and still others a large percentage of epidete. All these are products of metamorphism. These veins are noi auriferous, but in the center of the amphibolite J.A.Edman cleims that a one-foot quartz vein is auriferous. This vein is located by his Croesus and Pactolus Claims which are shown on the map of Edmanton. OUTCROPS. The only outcrop of the Diadem Lode is at the junction of the Big Creek and the Left Branch. Here the rounded and gray and weathered boulders of dolomite are exposed in a few places. That no exposure is seen at other places is due no doubt to the fact that the lode is less resistant than the more easily country rock oxidized,, and consequently covered with overhurden hiding the formation. Seco 0s asses Outcrop of the Diadem Lode on the south bank of Big Creek showing large gray dolomite boulders. @ - « * “© e 2 . a Amphibolite =schist foot-wall of the Diadem Lode at Edmanton showing the overthrow of the formation on the right,due to gravity and the nonresistibiliy of the soft and decomposed lode. The normel dip is shown on the left. At Chicken Flat, Big Creek has cut into and eroded the soft lode and formed an amphitheatre, leaving a flat of about two acres in the otherwise V shaped canyon. The length of the limestone could not be accurately determined as it is apparently faulted at one thousand feet southeast of Big Creek and is lost just northwest of Eagle Gulch. Prospecting at this latter point diclosed an East-West feult and the pink hanging-wall rock. GREEN 3STONE FORMATION. Resting conformably upon the slates is the greenstone formation including massive, schistose and clastic types, interbedded with what appears to be a metamorphic tuff. The variation of the greenstone is most marked and bears 2 resemblance to the description ¢f the " Greenstone 3chist Areas of the Menominee end Marquette Region of Michigan" Bulletin 62 U.3.GC.3. ORIGIN OF THE GREENSTONE . The structural relations of the greenstone formaticn with its variationms in texture indicates volcanic origin. Successive flows of basic eruptive rocks are intercalated with beds of tuff and pyroclastic material. After these were laid down the folding ecccured which formed the bedrock-complex. These rocks were compressed into a vertical position along with the other rocks of the series. The cempression forces were very great as shown by the fact that the messive rocks are on their borders very schistose; only a small central core of the larger original lava flows retaining the original massive texture. These rocks are of varioue types, the local variation being great, and due to dynamic metamorphism to which they were subjected. They range from a greenstone porphyry with half- inch lath=shaped crystals of plagioclase feldspar, showing distinct albite twinn= ing; tc a fine grained hard and messive rock, that has all the appearance of the Diebases. The ferromagnesian minerals are abundant and iron most plentiful; being scattered thru the mass in the form of pyrite. Pyrite crystals are found that have oxidized ; a coating of limonite relining the pyrite cavities. The rock shows a diabasic texture and the green hornblende is an alteration product from a pyroxene, probably an augite. Under the microscope the BasEive rocks of the greenstone formation show the same texture and minerals as the amphibolite foot- wall of the Diadem Lode, thus indicating the same origin. The clastic greenstones are harder than the ordinary massive greenstone and more brittle, due no doubt to the large amount of silica present. The brecciat -ed fragments are small, ranging in size up to two inches and very anguler, and having a rough crientation perpendicular to the line of application of the pressure that formed the bedrock-complex. The fragments are green and macrocrystelline to felsitic and cemented by a silicious tuff. The felsitic nature of the pyroclastic rocks prevented their microscopical determination. The angular fragments showed their pyroclastic nature by the difference in grain and texture of the adjacent fragments. The contact between the slate and the greenstone is in pleces definite; as at Big Creek and Eagle Gulch, and in other places indefinite. On both sides of Deadwood Creek the greenstone grades into the slates, so as 10 make a mottled intermixture of black slate and rusty tuff, indicating that both were deposited simultaneously. Along this contact the greenstone schists are much decomposed and in general weathered to a scft, yellow, clay mass, while the massive rocks shows none cf this decomposition, as they are eroded faster than weathered. PURPLE GREEN STONE 3CHISTS3. In the midst of the formation a large belt or strip of schistose to slaty greenstone wes found and examined. On the Oroville road the schistose green -gtone showed fine specimens of both the green and the purple variety interlemin- ated . The green color of the schists is changing tothe purple. In Snyder's Ravine this same formation is more slaty and shows little of the schistose structure . The color is grayish purple. Whether these rocks should be classed as slates or greenstone is & westion. The U.3.Geclogical Survey has classified them as the Calaveras Formation. In this same formation some of the schists have a mot tled grayish appearance, that looks very much like a tuff, partly altered and metamosphosed, and intimately mixed with some gedimentary material. GNEI330ID AMPHIBOLITE. Lying above the greenstone formation is a narrow belt of gneissoid amphibolite;= about five hundred feet wide at the northwest end and broading at the southeast end to a fan ghape. With this proading & distinct change in texture is noticeable. In the narrow part of the belt, the rock is coarsely gneissoid and the green rectanguler to almost square hornblende crystals are very large and coarse grained, snd flattened to a coarse schistose rock. A white mineral inter= lamina‘ed with the hornblende is an albite feldspar. Towerds the southeast, with the widening of the formation the texture changes to a very fine grain, the amphibole mineral is small and the gneissolid texture fine. In places a cquartz- schist is found. This schist comprised a small lens at the greenstone contact in Clear Creek at the Oroville Road. Towards the southeast a hard metamorphosed massive rock with a greenish color and a mottled appearance takes the place of the fine gneissoid schist. This rock undoubtly belongs to the gneissoid amphibolite belt but is more metemorphosed and recrystallized. SERPENTINE . Above the gneissoid amphibolite is a belt of serpentine rocks about four miles wide in all stages of alteration. These rocks comprise the bed-rock of the old Meadow Valley Lake. Above this basal member are the Tertiary and Quaternary lake gravels. The serpentine is an intrusive rock and shows little or none of the schistose structure characteristic of the other rocks of the bed-=rock complex. The only evidence of such structure is found along the gneissoid amphibo =lite contact and tion only slightly. Two different types of basic rocks are to be found; cne a peridotite in the vicinity of 3panish Ranch and the other a pyroxenite in the 3ilver Creek region. The first is a dense, massive and dark green rock with a very fine grain, and under the microscope shows olivine slightly altered with a good mesh structure The mineral antigorite is present in very good form. 3mall chlorite flakes are | sparingly scattered thru the rock and magnetite in grains is fairly abundant. ome of the metallic grains show a silver lustre. The pyroxene= amphibole rock of 3ilver Creek is no doutt a 29. differientiation product ¢f the same basic intrusion. The rock is coarsely crystalline, with a mottled red to greenish=brown color, and more readily de=- compesable than the Spanish Ranch peridotite. It weathers to a reddish mass. Abundant olivine is present and also, hornblende and diallage in slightly altered crystals. The mineral antigorite is here also shown in fine specimens, in slight =ly altered rock. Magnetite is present also. The only belt of completely altered rock is a belt of serpentine at the gneissoid-amphiboclite contact at the junction of Clear Creek and the Oroville road. Here the mineral serpentine is abundant. Chrysotile tho rare is present in small veinlets and here is the only place that it occurs in the mass. The rock is slickensided, due to swelling and slipping. The freshness of this basic belt is its chief characteristic and its massive structure indicates a late intrusion. GRANITES. West of Meadow Valley and including Spanish Peak is a large mass of granite that extends to the North Fork of the Feather River. This granite is a « . deep seated rock, exposed by erosion and shows all the characteristics of similar granitic intrusions of the range. It is of & medium texture and composed of both soda=lime and alkalai feldspars, little quartz, and sick hernblende and biotite; and also chlorite as an alteration mineral. Epidote is an abundant secondary mineral, that is develop- ed extensively along the joint planes. From its mineralogical composition the main rock mass is a granite and almost a granodiorite. The plagioclase feldspar, andesine, is very fresh but the alkali feldspar is so decomposed and kaolinized that a determination is impossible . The decomposition depends upon the nature of the rock. On the northeast end of the peak the granite is extemely resistant. one normal type of granite is here medium grained. The ferromagnesian minerals are indistinct due to alteration and the whole mass appears greenish, due to chloritization. On the southern end of the peak the rock texture is coarser and biotite and hornblende crystals are quite large. The rock is less resistant and has a great tendency to crumble and dscay. The glacial action on the northern end has left a smooth exposed surface of resistant and hard granite. BORDER FACIES. The mass is in general of a constant composition with a moderate abundance of ferromagnesian minerals. In some places these minerals form segrega=- tion masses. At the head of Big Crask a mass of almost pure ferromagnesian miner- als., are distinctive. The green hornblende is in excess; all other minerals being unimportant. This seme type is found one-half mile west of the Channel Mine at the north end of the peak and not shown on the map. The green hornblende of this rock resembles very closely the hornblende of the gneissoid amphibolite. About ninety percent of hornblende is present, a plagioclase feldspar and a very small amount of quartz. On the lower flanks of 3panish Peak near the slates and just above the Toll Gate, the granite is found to be almost lacking in accessory minerals. The color is light ,almost white, and the texture medium. The microscope showed both glassy and white feldspars, no quartz, and about seven percent of hornblende. The plagioclase feldspar which is the principal constituent is oligioclase and showed curved albite twinning, denoting strain. The rock is a diorite. An arm of the main granitic mass extends from Buck's valley easternly jnto Bear Creek. An interesting border facie was found near the basalt of Bear Creek and in the shaft of the Bear Creek Mining Company. This company was sinking to strike an old channel and in the Three hundred feet sunk, andesitic breccia, and a basalt dike, two feet wide was passed thru. When the work was discontinued The shaft had been sunk forty feet in the granitic bed-rock. Outcrops of the normal granite are within four hundred yards of the shaft.The type of rock encountered is a dark gray, holocrystalline and fine grained diorite with a greasy lustre, and a slightbrownish mottled appearance. 3oda-lime feldspar is abundant as is also hornblende and titanolivine. 3mall greins of magnetite is scattered thru the mass. Resorption is pronounced and the albite twinning fine and sharp and prominent. As both above and below the mine along the creek the normal granite outcrops, it is possible that this poikilitic diorite may bear a relation to the basaltic intrusion. GNEI330ID STRUCTURE . The granite is an intrusion into the bed-rock complex and in part of a later psriod than the compression which caused the fedding of the slates. The contorted and altered appearance of the contact is considered sufficient evidence of its intrusive nature. Whereas this is true of the granites of the north end of of the peak those at the southern end and in Bear Creek appear different in texture and structure, as was before pointed out. They show no marked contact phenomena and are in contact with a coarse quartz-mica schist which has been dissolved away by the later granite of the north end of the peak. This peak granite is in contact with the slates, with only a small area of phyllite bet- ween. This seems to indicate that the Bear Creek granite is an older intrusion while that of the peak is younger. That there was subsequent movement, after the folding of the bed=rock series or great compressive forces were acting while the granite was cooling and in » plasiic state is shown by the gneissoid structure of the granite which is traceable four hundred yards from the contact. S000 0000 Gneissoid granite outcrop, Spanish Peak six hundred yards from the contact showing a schistosity dip to the west. showing a Gneissoid granite, Clear Creek Cirque, 3panish Peak marked schistosity dip to the East. PARTINGS AND JOINTS. Throughout the entire mass of granite the joint and parting planes have broken the rock into rectangular blocks. This is most noticeable in the 3il= ver Creek and Clear Creek cirques which will be discussed under glaciation. Along these joint planes epidote is abundant; cementing the joints and passing ingensibly into the granite on either side. Crystal of epidote are prominent in some of the wider joints, and the alteration noticeably entends as much as three inches into the granite in some places. DIKES. In the great glacial amphitheatre many dikes are exposed on the glaciat -ad surface . The texture is variable, some having the same composition as the granite but finer grained, while others are composed mostly of the ferromegnesian minerals. In the Clear Creek cirque the dike rocks are mostly macogranitic. The dikes appear to reprasent the residual material (material) of the granite magma that was squeezed into the cracks of the cooling mass, and approach the lamprophyres instead of the aplites. All these dikes are small ranging in size from a few Shoko to not more than fifteen inches. In a characteristic specimen from the peak, this gray dike rock, while fine grained contained many lath-shaped crystals of hornblende, some biotite flake a little quartz and a small amount of magnetite, zircon and titanite. Very few phenocrysta are present. The feldspar is andesine. The dikes have no general parallelism but cut the granite into a reticulated mass. The dikes are not abund- ant . They are complimentary and may be called a mica lamprophyre in most cases. On the promintory of 3panish Peak a two foot pegmatite vein or dike composed of a granular quartz with a slight amethyst tinge, albite feldspar and a ; little coarse biotite mica is exposed, on the fault scarp. This white acidic dike was the only intrusion of this nature found in the granite mass and approached a true aplite. . ee 00009800 Pegmatite dike on the north side of 3panish Peak showing the glacial scraped granite below and a mica lamprophyre in the form of a segrega~ mass or largé dike above. 2200020000858 SUPERJACENT SERIES. The superjacent series consists of river, lake, and morainal gravel, and lava flows of basalt and andesitic breccia, lying unconformably upon the upturned and eroded edges of the bed-rock complex. According to Turner these comprise the sediments and volcanic rocks of the late Cretaceous, Tertiary and Quaternary periods. 35. TERTIARY PERIOD. During the early Tertiary period the indications point to a surface of low relief. In the absence of a uniform lava cover, the exact form is not everywhere traceable, but, the even and rolling topography of the larger land forms and the evenness in elevation of the remaining lava capped ridges clearly marks the older surface of erosion. 3ince this period the present river system has cut deep canyons. A great number of dislocations in the northeast corner of the Bidwell Bar Quadrangle precludes satisfactory conclusions as to the direction and flow of the old channels. The present relief is due both to faulting and to erosion. THE AURIFEROUS RIVER GRAVELS. The extent of the gravel deposits and especially just off the map and east of Spanish Ranch, indicate broad river channels. That an extensive river system covered the entire area is shown by the scattered remnants of the old channels; most of which are preserved by the lava and andesitic breccia capping. The nature of the gravel shows evidence of two or more systems of different age, an older and a younger. Unworked gravel, of the Gopher Hill Gravel Mine, one- half mile east of Spanish Ranch. Gopher Hill hydraulic cut, showing strata of tuff above the main gravel. Remnants of a small tailing deposit in Spanish Creek, from the Gopher Hill Mine. OLDER SYSTEM. The well rounded and metemorphosed gravels on Spanish Peak indicate the old drainage system. These gravels comprise numerous white, brown, and black quartz pebbles, together with extremely hard silicious metamorphosed rocks and conglomerate that show in striking (in striking) contrast to the more easily weathered rocks of the younger channels and the boulders of the bed=rock complex. No such rocks are found in the bed=-rock complex. Their worn and rounded appear ance indicates great transportation. On Spanish Peak the gravels are rarely larger than five inches in diameter. At both ends of the peak a channel has been tapped but the great depth of the pipe=clay and andesitic breccia in the form of a mud flow caused the discontinuance of mining operations. Where the channel was tapped the smooth granite bed-rock and lack of gravel indicated that at this point the river passed thru a deep and narrow gorge. The smooth bed=rock failed to catch the gold which is found in abundance in other channels of the same age. Along the Butte Bar trail in Bear Creek, these same gravels are scatter= ed over the surface of the andesitic breccias. They must have been collected by the mud flows at the time of the great volcanic eruptions, and subsequently exposed by erosion. Tn the Channel Mine on the north end of 3panish Peak the remnant of an old lake was tapped in drifting for the Spanish Peak Channel. This old lake contains ten feet of rounded and water worn gravel of the older svstem, but besides ,volcanic pebbles that are not found in the earliest channels , and also not found in the younger channels that contain so much volcanic rock. This gravel may indicate a later river system, but still included in the older river systems. YOUNGER 3Y3TEM . In the younger gravels the rocks of the bed=rock complex are found, and with them pebbles of andesite interbedded in the gravel and not a surface 38. detritus. Most all of these gravels are partly or well water worn, and are so altered to a soft ferruginous mass that on dropping they will sometimes break. Whereas no gold has been found in abundance in the older Spanish Peak gravels , those in the vicinity of Spanish Peak and Meadow Valley of later origin were rich. The gold of the later system is all coarse and as a rule well rounded, with the exception of the gold at Edmanton. Here the old channel was above the Diadem Lode and followed it for a distance. Above th e bonanza and in the gravel gold nuggets of ninety and sixty ounces were found accoeding to J.A Edman. It was this large pocket that supplied the streams around Edmanton with placer gold. There are few quartz veins of great productiveness in this teritory and all are pockety. esesssssses Sd 3cad Point Diggings, near Edmanton, showing volcanic gravels overlaid by a three foot stratum of pipe=clay. 39. Mumford Hill Hydraulic Cut above the old channel at Edmanton. The cut follows the strike of the lode. jome of the channels under the lava cappings contain an abundance of petrified wood in a good state of preservation. This was especially noticeable at the 3tar Plumas Mine in Bear Creek, where the gravel lies on a soft granitic bed=rocke. LAKE GRAVEL3 IN MEADOW VALIEY. In the Meadow Valley depression area which will be treated under faulting the gravels are in abundance and show the early Tertiary gravels, volcanic gravels and the later Quaternary gravels in marked contrast. Invariably the red soil and silicious pebbles mark the older Tertiary surface which covers the area in the valley. Some of the red soil is due to the alteration of the serpentine. The terraces and slopes on the border of the depressed area indicate that the valley was covered by a body of water, and the topography shows that finally an outlet was obtained thru the narrow canyon of Spanish Creek on the East, which flows into American Valley, resulting in the complete drainage of the area. All indications point to a depressed area or interior basin into which the Tertiary rivers flowed and deposited the Tertiary lake gravels. West of the 3ilver=3panish Creek junction is a body of cement gravel, composed of small, red, brown and white cementing material in the form of a tuff. Andesitic pebbles are in abundance. This gravel is auriferous and has been well worked. Above the late Tertiary gravel is the Quaternary gravel that consists of granite, greenstone, amphibolite and slate intimately intermixed with volcanic material. All of the morainal detritus is included in these gravels, which seem to have a direct relationship to the period of glaciation. It is probable that the glaciers from 3panish Peak collected these gravels and the streams deposited them in the valley, after the drainage of the lake. The drainage of the lake towards Quincy was due perhaps to the elevation of the region, which caused an increase in the volume of water and hence an overflow. TERTIARY VOLCANIC ROCKS. The volcanic rocks about Meadow Valley can not be called abundant, but they are well scattered and in small patches, which indicates that at one time they were abundant and probably covered most of the old surface. The two volcanic rock types represented are basalt and andesite. The origin of these volcanics is problematical for, to cover the region immense outpourings of lava must have been necessary. No large volcanic vents are to be found in the immediate neighboorhood that could have supplied these lavas. ANDE3ITIC BRECCIA. The andesitic breccia is a mud flow and consists of massive and vesicular gray andesite boulders, both rounded and angular, in a light gray ground -mass of a tuffaceous and silicious nature. The boulders are porphyritic to a soe RITE greater or less degree, the phenocrysts being either a plagioclase feldspar or a black hornblende up to three=sixteenths of an inch in length, or a combination of the two. The larger part of this material occurs in fragmental or pyroclastic ~ form and may be called andesitic tuff, breccia, conglomerate or agglomerate as the case may be. In general the matrix of this agglomerate easily weathers and the boulders are left scattered over the surface. On the Butte Bar Trail in the eastern part of the area the large mass of andesitic breccia contains andesitic boulders of great variety, ranging from a hornblende porphyry to a feldspar porphyry and in color from light gray through pink, red and brown to a dark gray. The highest contact point in Bear Creek, 5,200-feet elevation, to the lowest contact point in Meadow Valley, 3,800 feet in elevation, shows that the old surface slopes towards Meadow Valley with a comparitively gentle drop of about three percent. It is also noticed that the lowest contact point on the four sides of the old Meadow Valley Lake, the cement gravels being considered as the andesite flows is 3,800 feet. This shows that no movement has caused a tilting of the valley area, since the andesitic flows. On the south side of Island Hill are two patches of pumice that belongs to the same period of eruption as the andesitic breccia. While the immediate source of the breccia is not known, the field evidence clearly indicates that the andesite musthave come from the higher parts of the range. The rounded pebbles of andesite and the included earlier gravels shows that the source was distant and the flows first came along the old channels. When these became filled the mud-flows covered the entire region. On microscopical examination of these pebbles, which varies in size up to five feet, the average being three inches, considerable variation in texture and color was found. 3ome contained an abundance of ferromagnesian minerals while others contained mostly phenocrysts of feldspar. All however are porphyritiec, even the vesicular andesite which is not common. 42. Specimen Number 58. from a large five foot boulder in the old channel on the summit of 3panish Peak is very vesicular and undoubtedly a surface flow, or from the border of the mass. The vesicular nature is very prominent. The cavities are of a medium size and mostly filled with a pale blue chalcedony and yellow =brown quartz. The constituent minerals are feldspar and magnetite in a semi-glassy ground=-mass. No ferromagnesian minerals are visible. The toldapara are so decompos - =gd and altered to kaolin as to make a satisfactory determination impossible . Albitetwinning and zonal structure, which is characteristic of the andesites is rare. The phenocrysts are rectangular and in two generations. They seem to be cemented by a brownish=-yellow glassy base. Quartz is lacking. The texture is the hyalopilitic of Rosenbush or hemicrystalline porpyhritic. The refraction of the feldspar is partly below balsam. | Number 59, a pebble from the shaft of the Bear Creek Mining Companyin Bear Creek is a gray hard, porphyritic rock witha prominent eutaxitic structure. The phenocrysta are rectangular and tabular and in the ground-mass needle shaped. Albite and pericline twinning is very noticeable. The feldspar comprising nearly all of the rock is labradorite. Quartz is lacking and magnetite is abundant, but scattered thru the mass in small grains. Well formed augite crystals are also present(15%), showing a slight pleocroism. Its color is mostly a light grayish yellow. The rock is an Augite=-Andesite. Number 10., from the head of Snyder's Ravine and near the basalt is also an Augite=Andesite. This gray volcanic rock contains an abundance of phenocrysts, beth well formed, fragmental and resorbed. The structure is pilotaxitic and slightly eutaxitic. The groundmass comprises 35% of the rock and contains an abundance of magnetite. The augite(207) shows its characteristic ninety degree cleavage and square shaped crystals. Most all of the crystals are poikilitic, containing magnetite. The feldspar which is andesine shows seme zonal structure, good albite twinning and the properties mentioned above. 43. Number 15., an Augit-Andesite Porphyry from the top center of Clear Creek cirque is a gray dense rock considerably leached, the cavities being filled with a yellow quartz. The augite is abundant(407%). The feldspar is an acid andesine . The structure is identical with number 10. From the above it is noticed that the andesites contain augite to a greater or less degree and in general texture correspond. The andesitic lavas differ from the basaltic lavas chiefly in containing more acid soda-lime feldspar, with usually no olivine and less magnetite. BASALT. Two ages of basalt are classified in Turner's report, namely (1) the older and (2) the younger basalt, the little that occurs near Meadow Valley being called the older basalt. According to the U.3°C.3. the chief characteristic of the late basalt 1s its abundance of olivine, contrasted with the early flows which are not so rich in this mineral. At the head of Snyder's Ravine the basalt is found apparently above the andesite. This may be accounted for by considering it a volcanic vent, in which case it may be older. In the shaft of the Bear Creck Mining Company a two foot dike of this same basalt cuts thru the andesitic breccia and is the source of the basalt four-hundred yards West. This clearly places the basalt as younger than the andesite. Boss oReOELE Basalt outcrop near the Bear Creek Mining Company's shaft in Bear Creek. At the head of Big Creek a small patch of andesite was mapped by the U.3.Geological Survey, but this was found to be basalt, under which a small strip of gray rock of andesitic appearance was found. The basalt of the region is very dense, fine =grained and black, containing much iron. In places the basalt is speckled with iron, and amygdaloidal cavities are lined with botryoidal masses of hematite. The separate patches or masses of basalt are at an elevation of 5,100 feet with the one exception at the head of Big Creek, where it is at an elevation of 6,100 feet. That these widely separated masses show equal elevation is a good indication of the old surface of erosion. That one mass is 1,000 feet higher én the western border indicates that faulting has taken place. This difference is on the western and the eastern side of Big Creek. From the general distribution of the basalt the comparatively gentle slope of the old surface of erosion is marked. The conclusion is that the basalt of this district is the younger type and this is checked by microscopical examination, which shows abundant olivine. Of the great basalt mantle all hut small portions in scattered spots are eroded away. Specimens Number 300 from the 3tar Plumas Mine, 301 from the head of Big Creek anf 302 from the head of Snyder's Ravine were studied under the microscope, and all showed the same textural relationships. Number 302 , from the Star Plumas Vine was the most vesicular of the three specimens, but even 80, was quite dense and fine-grained. Amygdules up to three=quarters of an inch in length were abundantly lined with hematite, but these larger ones were rare. The average size was one-quarter of an inch and in most cases they were solid(or almost so) hematite. Megnetite is very abundant in the rock. Number 300 from the Head of Big Creek is a dense, fine grained black rock with smaller amygdaloidal cavities, up to one-eighth inch in diameter . These are almost spherical, but not sbundant. Number 301 from the head of Snyder's Ravine was collected from & small one-hundred foot mass that was above the andesite . This rock is the denser of the three and contains less iron and feldspar. The intersertal structure is prominent. An abundance of microlites or small lath-shaped feldspar is scattered thru an clivive groundmass. No orienta- tion or flow structure is discernable. Despite the fact that the plagioclase feldspars are small and narrow; albite twinning is quite in evidence. About 45% of the rock is feldspat which was determined to be an acid labradorite. The olivine is very abundant, cemprising 55% of the whole and forming the matrix in which lie the small feldspar crystals. Magnetite in varying amount from two to ten percent is scattered thru the olivine. GLACI ATION. Glaciation has played an important role in the history of the region. 46. On the north side of Spanish Peak a cirque two miles across, once formed the gathering grounds of the snow, which formed gla ciers and subsequently laterel moraines over one-half mile long and three hundred feet high. 3ilver Creek and 3panish Creek have their headwaters here and there is little doubt that along the channels the Quaternary gravels of Meadow Valley found a passage .On the east side of the peak above the Toll Gate a smaller cirque supplied the detrital material into Clear Creek. At Edmanton are two small patches of merainal gravel. The lower limit of the gravel at all these points is at an elevation of about 4,300 feet. The gravel is composed of angular to sub-angular boulders of all the rocks of the region varying insize up to seven or eight feet, the average, however , being about two feet. Glacial striations are lacking on both the smooth granite surface and the transported boulders but the unsorted mixture of very fine to coarse gravel is sufficient evidence of its glacial character. On the north side of 3penigh Peak three typical glacial lekes are form= ed in the cirgue and the fourth and largest called 3ilver Lake covers an area of about three hundred acres and is partly in the granite and partlyin the morainal gravel. In the Clear Creek cirque five drained lakes of recent erigin and now covered with grass and timber show in marked contrast the the otherwise rough cirque. { At Edmanton, the morainal gravel is aurifercus and paid well to hydreulic and drift into , especially near the Eagle Gulch side where the creek waters had partly concrentrated the geld. The large boulders, however, were & great hinderance to mining operations. ess bd0enee Clear Creek cirque on the eastern flenk cf Spanish Peak and above the Toll Gate, showing the remnants of small glacial lakes. A drained glacial leke in Clear Creek cirque, showing the distinct line between the leske alluvium and the granite . Spanish Peak end 3ilver Leke locking northeast and showing glacial lakes and brush covered lateral moraines in sharp contrast to the smooth granite surface with the Grizzly Mountains in the back- ground. Spenish Peak Lateral Moraines. 3ilver Lake. RETAKE OF PRECEDING FRAME Spanish Peak end 3ilver Leake locking northeast and showing glacial lakes and brush covered lateral moraines in sharp contrast to the smooth granite surface with the Grizzly Mountains in the back- ground. h Peak ot Speni Lateral Yoraines . Silver Lake. HAVYHA ONIAdIOHAAd AO AMVLAA 49, 3ilver Creek cirque locking West toward Mount Pleasant from ji Spanigh Peak. On the right is the morainel gravel and on the left the () smooth granite. The sharp end distinct line of ccntect between the granite and the moresinal gravel can be followed from Mount Pleasant one mile East toward Spanish Peak. Then eS Re i a Ra i: RL ; ET | v ~ f » J ed We “JN ee ( spanish Peak fault scarp partly destroyed by glaciation showing a large lateral moraine on the right. i. > : = QO Z - fe © z a fe Q 2 <« pt z 3ilver Creek cirque locking Test toward Mount Pleasent from Spanish Peak. On the right is the morainal gravel and on the left the smooth granite. The sharp end distinct line of ccntact between the granite and the morainal gravel can be followed from Mount Pleasant one mile East toward 3Spenish Peak. spanish Peak fault scarp perily destroyed by glaciation showing a large lateral moraine on the right. 3ilver Creek cirque, looking West toward Mount Pleasant from Spanish Peak , showing Gold Lake in the foreground. 3ilver Leke , in morainal gravel showing granite in background . FAULTING. From the steep canyen slopes, saddles and scarps, evidence of faulting je to be found. That the country is much feulted there is no doubt, « Mr. Edman states that in the Diadem Mine much evidence of cross faulting is found. Along the Diadem Lode there is evidence of faulting, shown by the brecciation of the lode material, and a slight offset in Eagle Gulch. In the Diadem fault zone no gouge is found, but instead a quart z=breccia, which indicates a small throw. The difference in elevation of the basalt on the East and the West side of Big Creek, together with the stcep and high slopes of Big Creek indicate faulting with at least a 1,000 foot dislocation, with an elevation of the West side. On the summit of Spanish Peak is found the andesitic breccia at en elevation of 7,000 feet which occurs in the valley below at 3,800 toot. Te Peek rises abrubtly above the valley 3;000 feet and slong the eastern side a most imposing fault=scarp can be followed for two miles. At Edmanton this fault is offset and runs along Big Creek into Bear Creek. The Diadem fault is & minor dislocation which follows the Left Branch of Big Creek. The successive veination zones in the slates numbering at least six, seems to indicate zones of movement and successive step faulting that caused the elevation of the peak. Under present cenditions glaciers will not form under 13,000 feet and as great glacial action is seen on the peak which is now only 7,000 feet in height the conclusion is that at some previous time the 3panish Peak region was elevated to a height of permanent snow, with consequent glaciation. and subsequently dropped by asecond dislocation to its present altitude of 7,000 feet. This of course is assuming present conditions. It is possible that the peak was elevated only and a different climate was favorable to glaciation. A change of climate leter would then destroy the glaciers. Spanish Peek looking West from the Butte Bar Trail, showing the nature of the vegetation, the fault scarp and the uplifted region of the Peak. The depressed area below the Peak and on the right is the Meadow ! Valley lake basin. RTS TE ERT spanish Peak looking West from the Butte Bar Trail in Bear Creek, showing the fault scarp, moraines on the right, level top of the 3panish Peak channel, and the nature of the brush covered hills. RETAKE OF PRECEDING FRAME Spanish Peak looking West from the Butte Par Trail, showing the neture of the vegetation, the fault scerp end the uplifted region of the Peak. The depressed area below the Peak and on the right is the Meadow Valley lake hasin. spanish Peak locking West from the Butte Bar Trail in Bear Creek, showing the fault scarp, moraines on the right, level top of the Spanish Peak channel, and the nature of the brush covered hills. Big Creek locking South from Edmanton along which the Meadow Valley fault runs into Bear Creek.... 29 4000098600 The geological sequence of the northern part of the 3ierra Nevada Mountains as exposed in Meadow Valley, show Carboniferous sediments and thin bedded limestone due to calcareous deposits of forminifera . These were raised above the sea level and evidently exposed to erosion. Volcanic activity on a large scale deposited volcanic sediments and rocks in the form of basic eruptive lava, tuff and pyroclastic material above these sediments. Some of the volcanic rock intruded into the sediments as large lenses. Creat compressive forces acting in a northeast=southwest direction closely folded these formations. The great granitic intrusion in the form of & batholith took place. After the folding the peridotite or serpentine of Meadow Valley was intruded in the form of a narrow belt or wide dike. The freshness of this rock and its nonschistose nature clearly indicetes & late intrusion. Subsequently a long period of erosion followed and the folded formations were eroded to a surface of low relief, exposing the granite batholith and the vertical and upturned edges of the bed=rock complex. The folds ; are entirely eroded away. On this low surface of relief the broad and oldest rivers flowed and collected the quartzose pebbles, so characteristic of these channels. Andesitic and basaltic eruptions now broke out and covered the surface with a mantle of volcanic material and at the same time much movement caused a second elevation of the region. 3treams immediately began to cut new courses and the later river systems were formed that contained abundant volcanic boulders and pebbles . The result of this extensive movement and dislocation was the elevation of the Spanish Peak region into the zone of permanent snow. This pericd of faulting may be considered a third period of faulting, or the final result of the long and interupted epoch. Again the drainage was changed and the present river systems were formed. Glacial action on 3panish Peak which was the gathering grounds of the snows in this region, cut the 3ilver and Clear Creek cirques. From 3panish Peak glaciers rediated in all directions. The present Quaternary gravels were laid down and the land sculptured to its present form. The Meadow Valley depression area which was formed during the period of low relief, was a lake thru the andesitic eruption period and finally drained during the final feulting that caused the elevation of Spanish Peak. CrLIFORNIA. Flare T Clausen: Meadow Valley aE & Thesis > W Bn er AN DOCUMENT FILMED IN SECTIONS heed] Tg] Tg oa gpa 1/3714 15 meTmig er Cc a lt —— S— -— — C & © MOnUImentay = = = i Ll I a ) oHornbrook Q " CRE T lr SCEN ’ CITY O YREKA, oMontague 5S Kil: yY O oEdgewood oSisson i { ak Dunsmuir / osm - oDelta or Be mena Tre ia He" Q Jiohnerville s hl < OREDDING No) Olpper Mattole a Block sbur eosin T EHAMA-A oTehama 7 oforning Hn oNimshew > Bo ico TN GL E N N By A . OFrute ! - A Biges se. 1 - ights™\ dy NA WOODLAND \ WE 1 Y O L Osac v o Nf sieze », rn — / FrRoss O \. / 1 4 \ No Vgeaville | ( N17. SANTA A Rosa ws o ( RioVista ’ J] NET ee Liek?i00{ $_OSANJOSE ‘ ) \.. UT TE Patermoy T - — — QO DD Q C oALTURAS Cedarville © - — Q / pT “Obeorgetown Rockiino § E'L DORADO .— ar om P \ al <0 \ Leman, ' S$ Fo + rn anit SR ALPINE © —" FMA Pb i © J NL 7 1SOL ANGORA. dor | oo & 7 el vv ir 2 FN F Ne Fi TUOLUMNE ~ i oJamestown eed \. Ok Ne ~Huanizesa ” ~~. TTI Latent : 3 A 7 ‘wovegTo Owestly - -— » : ) MAR IPOSA > So Sa 7 N or ' ll Q / 7 oMERcED \ or of M E R Cc £ D Ae oo — 2 Leg Banos o£ 7 ] © o Story 7 L MADERA Q . MAP OF CALIFORNIA SAN odanta Margarita Ly, s Lois oBIsPO ans Santa Maria SANTA BA 1 RBARA SANTA wens J o VISALIA OTulare olemon Cove o Porterville oBAKE RSFIELD E R T U LL A R E v y ~— ho & A 7 7, t Sogomal| \ SOLAN O fen gary. um &° i i. N 3 4 i py eX ~t N % . [50 wp Caf Ghdtioch oi 7 ™, » ol Wadi T= erocipn F 5 7 TuoLumne \ ° bo SR ONTRA COSTA | 0 \ fll odamestown N X aie 2S > fA Jpn hey 4 N KLAND ii Trac ' \ ! _- ~~ \ “ ~ oY He | > LTT od Livermore o> 5 5 \ —— Zh oO MN Niles, Ye / mooegTO no A 7 . ) Og t 7 wey ov .-AMARIPOSA LN Nn = ST \ rT » i ™N > i \ oS ( VADERe. hy < x & \ 4 “Ni Zz \ ry \ & > Vv ~ \ 2 v NAS \ a FRESNO rr ; 5 S44 NN & \ Mendota oSanger ._ _. |] \ Monterey & : WE ———— ———— ————— | ————— on ————". ———— A \ ¢ \ 2 QVENTURA 7 po oT xr =, \[-08 ANGELES 0 Santa Monica A ee. v fl } 0LOS ANGELES ) | { OL Ras & Neg — ———— i —- —— a — | ———— - He ————— a S——— — o—— | s——— — —— ——_ o— r o Redlands -— ~de -d o Cabazon | NW RIVERSIDE / \ SANTA ANAN R | o El Cajon SAN DIEGO ———— —- ————— -—— - —— | ————— o Palm Springs Vv E SANDIEGO —— MP ERIAL RIAL o!MPE Calexico -- — -- bi SL slay Prumas County. Plate Ir | Clausen: Meadow Valtey < Thess > v DOCUMENT FILMED IN SECTIONS TINE ROCK NN 3 8 3 2 STOVER MT » PH DEVILS <, vir 4 880 — cOUNTy PLUMAS CALIFORNIA ISSUED BY THE STATE MINING BUREAU A. §. COOPER STATE MINERALOGIST TRUSTEES Ww. 8. KEYES ALEXANDER F. MORRISON THomas B. misnop UE POOLTTLE VICE PRESIDENT Si J. A. EDMAN FIELD ASSISTANT COMPLIMENTS OF W.H. STORMS STATE MINERALOGIST Note: Area mapped colored red. S “A Geel J BVIEN \ ¢ {£ Papn LL LAS. Rs Loree Mod orrs Lf \ | odie) RESERVOIR L. BEN 3 \ OAK FLA \ T RUSH CR.HILL LS ! \ \ 1” PH DEVILS Sin 080 BRALTAR 5 4 GREENVI % PH DEVILS < Arkor 7 Rs GIBRALTAR # » ! | 4 v { ki ! RL ; Ll sii) iA ane UR big HER ind a | 4 oa frp Him ei IL; Ge ologic bi Rar wer ned Ee (hu sid A # fi Ere t aan be Te in tod PLR RIN i Ea I I i I ae BESTE bi ld EE Es a 3 Ta AE Jp en His DOCUMENT FILMED IN SECTIONS “wm, ! No i Pi RL Xi 7 | Be \_ /o\ J ==] — JE [FORNIA \ 4 C E HClavsen 0 { ~ @ = 1) > Q & D @ i CO ranodiorite. 3 J G 3 A L het > wm £ od Q = Ld Mica Schist Derpentine Andesitic Breccia E88 Silicified Slate BEE ccione Tertiary Gravels intervolcanic Gravel i Mra a —_— * “ I i Fa (fr = | ( AT d bo ve = lca ¢ 7 : 7 AI ARTS ET TETRA / / i ( 77 7 ———— AVIA ONIAAD TUL 40 AMV.LAN is es ali PEERY EMRE Erp erent | TTT Tr TTT TTT TTT IT rrrpT (A lM RE BR LTE PR ob) zl ot: le. 18. 1&8: ls, [v: le, [2, |r suis elt gl tL Olt 16) 18) 181 lS lll 4 GEOLOGICAL SECTIONS to accompar map of MEADOW VALLEY ANDO VICINITY PLUMAS COUNTY — CALIFORNIA. Geology by E Flleusen Scale Horizontal 11n-7000F%. Vertical 77/n -300 Ft Note: True dips are shown. ranch Bucks ey US Bear Creek 7-517 NZ sos Gulch Bear Ck 7ra:/ ’ ench Snyders Creea. Snyders Creek. Butre Bar 773:/ Big Creek ~ ft Branch B/g Creek. Taylers Creek. Z g Granodiorite. x @ Q x ] Q Ww QS 2 3 v Q x S = g © 0 ~N 3 by, ~ ~ N Seer . UE Bear Creek Trail. Culch Besr Creek 7re// Big Creek rch of Snyders Creek kA > 2, Sr yders Creek Big Creek Lelt Branch 19h Andesite Breccra fer Rack Cree / Branch Serpentine ile tho Creenstone FoerD Oooh ASLEM PES Ly 1184s gr Sppn&T Yoe4 Breccia Andesite ¥824D ssophug jo yor gr yb. ¥2919 s07hey — EAL ¥934D 4836 ¢yn SH be 7 . ¥oo40 big yo CELET 143 T J1EAL O34) yo045 beg ¥29./. 5 8 LIP AICS Yous 1/3 T Granodiorite Greenstone STH [84 4eg7 PLANET YoesD AEF YI0 4 LR L [AS Andesite Breccia ~— Moo ’ “Cogr 3 +f Y/40N/ ~ VOOA) SCUN ef 44S Youessr 7 YaI4) Sens LE YouECL LT iAP 7 Breer Grenodiorite Aemorrier yoos5> yoo4) big Gower fa yoorD bre \ — Andesite \ Tw UB mecers \ Granodiorite ead we Fer Amr phibolite Quartz - Mica Sehist | Greenstone -Grerssoid —Amphibolife. | | Big Creek reek Butte Bsr Tras/ Branch Big Creek Sock Drive wey Left Branch Srar Dumas Creek Andesite Breccia North 7-7 Boy, - Fork Besr Creek Right Bronch Siar Plumas Creek Ves Sechist es ———————————— Granodiorite wor Ve —— — Ns er m—— So —— ———— + MT TT ——" T— ET TS ———— TT WS ERE 1 SS ST Se pu a pm el slivoibon ppp gE Ve e ly =| It .olt, 6, |8 a) g |b g, |d woh ct zn non 6) 8 40 90 Bi Soli Ein im pe Th a GEOLOGICAL SECTIONS to accompany map of} MEADOW VALLEY AND VICINITY Geology by E.HClausen. FLUMAS COUNTY —CALIFORNIA. | Scale x Horizontal 11In=1000F1. © Vertical 1In=300 Ft. . Note: True dips are shown Q 4 5 a 0 J v = v 5 = Mica Schist. Q m T 5 t -~ © v 5 Qo i ’ BS = o x Qa. i Q 0 iy p vw x Gravel Q Q ¥.2 - - Op x XX Q® o - a — oo y 2 x 9 a . er ry + - Py} Granodiorite rave S o 0 v 9 x 3 ; : O 0 £ ox x v x » © < § ; % § : Clay Slate zg S $ x 3 Xo - © 2 N c 3 £ TE Tv nN . 3 ; ter- Volcanic v g > s Vv £.9 s 9 4 P rr > “3 3 § Greensione O 0 0 0 em OO E AE Quaternary Grave Tertiary Grave Serpentine. eee inseam ? 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Plate YI Topographic Map, Edman Mime Clausen: Meadow Va ley Thesr's WE YMOTH QUARTZ LPC rato ol ”~ - \ ”~ e,” 2, 3 A. &’ / / 7 ’ “ -T \ A Seer NN, Cel HESPRRIAN N LerT Sl , - QUARN Z i { gl N C 7 wr © Py LAI i 0 ANON PLACER C 2c Eagle cules / » vi A Legle ; : . { , : EAST - GATE PLACER XR CLAIM. y ’ Lei / c.29. 3 Sec.28. JL | T : ’ ~ oT QUARTZ CL. LLY rT \ LT ) . - 1 aT : vic#oR or. CL. om 7 | - Timber Shed |i oO ) r . qt" ~ 1 ~~ y 1£¥ \ L $ yA o ye J Wo \ ay- \ ME in? 7 g, 7 a Pt Sec32 e Sec33. Ms © ” . = ig 0 C 27 P > -~ ¢ > > Je Dwell z ™ Bonansa- haft Old Shop. a 7 3 Z © ANE « BEAN NG » Board -—" * wh H md NA o\ | DAADEM QU. CLAIM, \ § bY 3 A > 8 0 Ry z Mull] S hy HELL AS CE A, <3 & BR CLAIM a OD Coa\ Meu / - ik-Head EW 5 > » A 20 PN 5 > UK Hea i Yon \ \ \ x : > \ ALBION PLACER CLAIM pr dix \ RED-POINT QUARTZ CLAIM, \ | \ \ \ \ \ Sr V7, 2 \P NF CLAM- FISH SPANISH PEAK - PL UMAS CO : QUARTZ LOCATION. © 4 Topography by Traced by \ C.E. 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