ILLINOIS STATE GEOLOGICAL SURVEY 
 
 3 3051 noons sans 
 
Digitized by the Internet Archive 
 
 in 2012 with funding from 
 
 University of Illinois Urbana-Champaign 
 
 http://archive.org/details/landslidesalongi48dumo 
 
GN 48 
 
 557 
 I16e 
 no. 48 
 c. 1 
 
 ENVIRONMENTAL GEOLOGY NOTES 
 
 JULY 1971 • NUMBER 48 
 
 LANDSLIDES ALONG THE ILLINOIS 
 
 RIVER VALLEY SOUTH AND WEST OF 
 
 LA SALLE AND PERU, ILLINOIS 
 
 Paxil B. DuMontelle, Norman C. Hester, and Robert E. Cole 
 
 ILLINOIS STATE GEOLOGICAL SURVEY 
 
 JOHN C. FRYE, Chief • Urbana 61801 
 
URBANA 
 
LANDSLIDES ALONG THE ILLINOIS RIVER VALLEY 
 SOUTH AND WEST OF LA SALLE AND PERU, ILLINOIS 
 
 Paul B. DuMontelle, Norman C. Hester, and Robert E. Cole 
 
 INTRODUCTION 
 
 In 1931 at the Illinois Academy of Science, Dr. George E. Ekblaw, 
 engineering geologist with the State Geological Survey, observed: 
 
 As most people associate landslides with mountainous , hil- 
 ly, or rugged country, and as most of them also seem to be imbued 
 with the misconception that Illinois is nothing but a flat, monoto- 
 nous prairie, the statement that in this State landslides are very 
 common generally occasions some surprise. Only those who through 
 bitter experience have learned otherwise and those who have actually 
 studied landslides appreciate fully the true situation. Despite the 
 fact that landslides are common and do frequently present trouble- 
 some problems, they are not serious and possess no great potential 
 dangers in Illinois. However, the prevalent false idea that they 
 are non-existent engenders utter disregard, and this in turn does 
 pave the way for preventable disasters. 
 
 The Illinois River bluff near La Salle and Peru (fig. l) is an area 
 in Illinois where landslides are common. Because the Illinois River barge sys- 
 tem provides low-cost transportation for the region, industrial growth is ac- 
 celerating along this river corridor. With the construction of a major steel 
 plant at Hennepin and its associated service industries, the accompanying pop- 
 ulation growth is requiring a greater number of home sites (McComas, 1968) . 
 
 Because many home builders desire a site with a view, they have tended 
 to concentrate thus far on the Illinois River bluffs. An excellent view of both 
 the river and nearby cities is provided from the top of the bluff, which rises 
 nearly 100 feet above the river floodplain. 
 
 - 1 - 
 
- 2 - 
 
 Heavy rainfall during the 
 spring and summer of 1970 triggered 
 slumping and earth flowage of por- 
 tions of the Illinois River bluff 
 south of La Salle and Peru, causing 
 serious construction problems. The 
 Illinois State Geological Survey- 
 was requested by several home own- 
 ers in the area to make an investi- 
 gation. Road reconnaissance and 
 field observations in the region 
 indicated unstable slope conditions 
 along the Illinois River bluffs 
 from Oglesby to a section about 10 
 miles west, near Allforks Creek 
 (fig. 2). Subsequently, an aerial 
 inspection with low-altitude, ob- 
 lique photography demonstrated the 
 extent and type of slumping and 
 sliding in the area. Samples of 
 geologic materials were taken at 
 one locality and tested for both 
 geologic and engineering proper- 
 ties. 
 
 This report outlines the 
 general landslide hazard of the 
 area for the general public, parti- 
 cularly for people engaged in plan- 
 ning a construction project on or 
 near existing or potential land- 
 slide areas. It describes some of 
 the slide areas in detail, shows 
 how the areas of sliding are di- 
 rectly related to the geology, and 
 discusses possible causes of the 
 slides . 
 
 Pig. 1 - Index map and township (6 miles by 
 6 miles ) showing study area and location 
 of Illinois Valley Community College. 
 
 Acknowledgments 
 
 James C. Gamble, University of Illinois, made the slake durability 
 and Atterberg limits tests on our samples. Dr. Robert K. Morse, Consulting 
 Engineer, El Paso, Illinois, provided information about the subsurface of the 
 area and helpful discussion of problems caused by the unstable slopes. Ross D. 
 Brower, Illinois State Geological Survey, photographed locations 5C and 5D 
 (fig. 5) and discussed the geologic problems with some of the land owners. 
 
 GENERAL AERIAL SURVEY 
 
 A series of low-altitude, oblique photographs were taken along the 
 Illinois River bluff from Oglesby to Allforks Creek, at points shown on figure 
 
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 Location 1 - Terracettes formed by slumping alor^ 
 small tributary of the Illinois River. 
 
 Location 2 - Bluff slope showing recent cracks 
 caused by slumping. 
 
 Location 3 - Large well developed landslide abov< 
 buildings on the slope of a tributary valley. 
 
 Location 4 - Bluff slope of the Illinois River. 
 Arrow indicates a recent small slide. Shadows 
 show positions of older landslides. 
 
 Location 5 - New home constructed along the bluff 
 Recent landslide obstructs road. Fracturing ar 
 slumping are visible above and to left of house 
 
 Fig. 3 - Oblique aerial photographs of landslides in five locations along the south bluff 
 slopes of the Illinois River. 
 
- 5 - 
 
 The unstable slope condition -was observed principally in the region where the 
 Bond Formation, a shale of Pennsylvanian age, crops out as shown on the figure. 
 Selected photographs taken at five locations (fig. 3) show the type and lateral 
 extent of slumping. All the photographs are views looking south toward the 
 bluff slope. 
 
 At location 1 (fig. 3), a tributary creek flows north toward the Illi- 
 nois River, truncating the bluff slope. A series of slump blocks have developed 
 terracettes on both sides of the valley. An attempt is being made to stabilize 
 the slope below the home on the right, or west, side of the valley through the 
 use of sealing, draining, and cribbing. Construction on the homes ite in the 
 foreground on the left side of the valley was discontinued when cracks appeared 
 in the immediate area of the foundation. 
 
 The photograph of location 2 (fig. 3) shows a farm at the mouth of a 
 tributary creek. Slumping and associated cracks can be seen along the slopes 
 to the left of the farm and extending some distance up the slope. The steep 
 banks along the road resulted when slumped material was removed from the road 
 surface. 
 
 The photograph taken at location 3 (fig. 3) shows a major slump de- 
 veloped on the slope above the home at center left in the picture. Materials 
 that periodically flow are encroaching on the back yard. Slump cracks are evi- 
 dent along the north-facing slopes as well as on the east-facing slopes. 
 
 At location k (fig. 3), a small scarp and landslide have recently de- 
 veloped on the slope shown in the lower left corner of the picture. Many larger 
 scarp shadows from old slides are visible in the wooded area. These slumps 
 cause road maintenance problems. A scarp is a natural exposure of fresh earth 
 and rock material uncovered by slumping activity. 
 
 The picture at location 5 (fig. 3) shows the bluff slope about 2 miles 
 east of the mouth of Allforks Creek. Numerous scarps are visible in the left 
 half of the photograph. The newly constructed house is situated in the central 
 part of the slope. Active slumping is taking place both above and below the 
 lot. The slide to the left of the house buried the road below. The one-lane 
 section of road, opened when part of the slide was cleared, is offset 20 feet 
 from the original road. 
 
 RECOGNITION OF LANDSLIDES (SLUMPS) 
 
 Large landslides are readily seen from an airplane, but they are more 
 difficult to recognize when viewed from the ground, particularly during months 
 when foliage is dense. We have suspected that slides might occur on steeper 
 slopes in most of the area where shales are exposed, although there are some 
 areas with apparently stable slopes in this region. It is, therefore, impor- 
 tant to recognize the typical characteristics of unstable slopes. 
 
 The landslides associated with failure of the shales in this area 
 are called successive rotational, or slump, slides. As defined by Sharpe (1938), 
 a slump is "the downward slipping of a mass of rock or unconsolidated material 
 
- 6 - 
 
 Fig. 4 - Schematic drawing of progression of landslide (modified from Fairbridge, 1968, p. 699) 
 
 of any size, moving as a unit or as several subsidiary units, usually with 
 backward rotation on a more or less horizontal axis parallel to the cliff or 
 slope from which it descends." Figure k depicts this type of slumping, which 
 is common in the La Salle region. 
 
 Downward movement of the uppermost unit from the crown area may 
 occur relatively rapidly, causing a sharp cliff (the main scarp) several feet 
 in height to appear in a matter of hours or weeks. If such movement takes 
 place in a wooded, unpopulated area, such as that shown in figure 5A, it goes 
 essentially unnoticed. On the other hand, movements affecting structures, such 
 as the road shown in figure 5B, are noticed very quickly. 
 
 Poor drainage is a conspicuous feature associated with large slump 
 structures. The slumping of the units causes cracks and depressions near the 
 scarp faces and frequently disrupts normal surface run-off of rainfall and 
 ground-water flow (fig. 5C). As the cracks fill with mud and water, ponds 
 and marshes may form. Trees in this part of the slump usually die because 
 of root damage or drowning. 
 
 Another recognizable feature of unstable slopes is the presence of 
 trees tilted at various angles (figs. 5A and 5C). This phenomenon has been 
 referred to as "staggering forest." Some trees, particularly large oaks, may 
 
- 7 - 
 
 ride a slump "block down the slope. These trees may, in part, control the size 
 of the slump unit by holding together large masses of sliding material. 
 
 The units generally do not move continuously down the slope, and, as 
 is shown in figure 5D, some blocks may become relatively stable. Within a few 
 years the slope may look inviting for development. However, it is practically 
 impossible to predict how long the unit will remain stationary. Action of the 
 natural forces that cause erosion of the landscape will eventually cause re- 
 newed movement. 
 
 As units move downslope, they tend to break up and form a tongue of 
 flowing mixture of rock and soil, as is shown in the toe of the illustration 
 modified from Fairbridge (fig. k) . If these areas of mudflows are active, they 
 are often devoid of standing trees. As shown in figure 5E, the toe may flow 
 onto the floodplain of the adjacent stream. During spring floods, these slide 
 and mudflow materials are easily eroded or water-soaked, which rejuvenates 
 creep. Roadbeds in the paths of these flowing materials are often buried. In 
 figure 5F the ditch along such a road is being re-excavated to maintain proper 
 drainage for the road. As the toe of the slide is removed, the balance or the 
 stability of the slope is disturbed, and the cycle of landslide erosion is re- 
 peated. 
 
 SLIDES NEAR ILLINOIS VALLEY COMMUNITY COLLEGE 
 
 The site of the Illinois Valley Community College was chosen for de- 
 tailed study because landslide activity was evident from aerial and ground re- 
 connaissance observations, because the rate of creep has been monitored through 
 the surveying of stations by the resident engineer during the past year, and 
 because engineering test-boring data were available from Dr. Robert K. Morse, 
 Foundation Engineer and Engineering Geologist from El Paso, Illinois. Dr. Morse 
 recognized the problem of the unstable slopes and conducted a testing program to 
 develop for the campus an engineering plan that would stabilize the slopes and 
 prevent future damage to the structures . The treatment includes an engineering 
 design for reconstruction of parts of the slopes and control of surface water 
 run-off to prevent erosion and overloading of the slopes. 
 
 Aerial Survey 
 
 The new facilities of the Illinois Valley Community College are lo- 
 cated east of U. S. Route 51 near the south bluff slope of the Illinois River, 
 south of La Salle (fig. 2). An aerial view (fig. 6A) of the campus area looking 
 west shows the temporary buildings in the center, the Illinois River and bluff 
 to the right or north, and the new construction to the west. 
 
 Figure 6B shows the new buildings and their proximity to the adjacent 
 tributary valley of the Illinois River. The site is bounded on three sides by 
 tributary valleys with steep gradients. The absence of vegetation, and the 
 presence of exposures of the shale bedrock are due to sliding. The prominent 
 bench (white arrow, fig. 6b) along the lower part of the slope is a surface re- 
 flection of the more resistant beds of the La Salle Limestone Member. The lime- 
 stone is the lowermost unit of the Bond Formation (fig. 7). 
 
- 8 - 
 
 EXPLANATION OF FIGURE 5 
 
 A. Slump slide in a wooded area. Note arcuate scarp (light colored 
 outcrop) below the crown of the slide. 
 
 B. A road damaged by slumping activity and now abandoned. 
 
 C. The crown and main scarp (center and right) viewed after a rain. 
 Ponding and poor drainage can be seen along the back slope of the 
 first unit (center and left). 
 
 D. Top of a stabilized slump unit, seen here as a nearly level ter- 
 race, appears inviting for development. 
 
 E. Material slumping and flow (left to right) onto the valley 
 alluvium. 
 
 F. Piles of creep and flow material along the road that were dug 
 from the borrow ditch. Note crooked fence line and hummocky slope 
 to right caused by slides. 
 
 The larger scarps at this locality are about 15 to 20 feet high, and 
 ■were formed by slumping blocks of soil and rock. The slump blocks extend lat- 
 erally along the slope for 100 to 800 feet and form step-like benches , generally 
 20 to 25 feet wide. Continuity of the units is lost as the material moves down- 
 slope, which results in an earth-creep or mudflow. Material creeping down the 
 slope of the small valley south of the structure has completely filled the bed 
 of the stream (fig. 6c). 
 
 The proximity of the college buildings to the unstable slopes is 
 shown in the plan view photograph (fig. 6D) . To prevent further slumping, the 
 slopes are being kept as dry as possible. A maintenance road will circle the 
 complex as part of the water control program for the college grounds . A storm- 
 water system designed to intercept the downward movement of surface water will 
 collect this water at a location east of the campus and conduct it in conduits 
 to the valleys to the west. To prevent erosion of the slope, the drainage con- 
 duits will be extended below the limits of the outcrop of the La Salle Lime- 
 stone Member at an elevation of 520 feet above mean sea level. The unstable 
 valley slopes will be recut into benches, reconstructed at lower angles of 
 repose, and compacted to develop a more stable grade. 
 
 GEOLOGY AND ENGINEERING CHARACTERISTICS OF THE SLOPES 
 
 The geologic column and generalized cross section (fig. 7) summarize 
 the lithologies as they occur at the Illinois Valley Community College. Cap- 
 ping the sequence of sediments of the Modesto and Bond Formations of the Penn- 
 sylvanian System is a section of Pleistocene glacial deposits. Coarse sands 
 and gravels and scattered boulder beds commonly occur in the lower portion of 
 the glacial section. A series of till units, in some places separated by beds 
 
- 9 - 
 
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 Pig. 5 - Examples of landslide activity in the La Salle-Peru area, 
 
- 10 - 
 
 EXPLANATION OF FIGURE 6 
 
 A. Illinois Valley Community College campus on the south bluff of 
 the Illinois River Valley. Arrow points to new building con- 
 struction. 
 
 B. Construction site from the northwest is bounded on three sides by 
 steep tributary valleys. Arrow points to shadow caused by outcrop 
 of the La Salle Limestone Member. 
 
 C. Construction site from the southwest. Scarps, slump blocks, and 
 slides appear as irregular shapes and arcuate lines on the 2:1 
 slope. The large slide encroaches on the short tributary stream 
 (arrow) south of the structure. 
 
 D. Construction site from east-southeast showing series of slump 
 
 blocks and slides southwest of the structure. 
 
 of silt, rest on the "basal deposits. Loess and soil 2 to h feet thick cap the 
 bluff slopes. 
 
 The valley profile shown in figure 7 has a vertical exaggeration of 
 two; the true angle of slope is about 25 degrees. The slope failure pattern 
 is schematically drawn to indicate the kinds of materials incorporated in the 
 landslides. As observed in the field, the thin limestone units, except for 
 the La Salle Limestone Member, are generally unable to prevent slumping. 
 Pronounced jointing causes blocks of bedrock to loosen and slide downslope. 
 Ground water seeps from a series of springs located at several horizons along 
 the slopes, and springs occur along permeable bedding planes that lie above 
 less permeable beds. 
 
 Laboratory analyses of shale samples from bedrock exposures of the 
 Bond Formation in the La Salle region indicate that usually more than 50 per- 
 cent of the clay present consists of the expandable type of clay minerals. 
 Physical tests of the shale samples show that they are weakened by freezing 
 and thawing and/or wetting and drying. Approximately 50 percent of the un- 
 weathered shale consists of clay-size (less than 0.002 millimeters) particles, 
 and weathered shale contains more than 70 percent clay-size particles. The 
 weathered shales tend to take up water more readily than unweathered shales. 
 When the clays do take up water, weight is added to the slope, and the lubri- 
 cation characteristics of the materials are increased. Our tests indicate 
 this change is primarily a mechanical rather than a chemical alteration of the 
 shale. These data strongly suggest that the weathered shales are more prone 
 to sliding and slumping than the unweathered shales and that in many of the 
 slope failures only the weathered materials are affected. 
 
 EFFECTS OF CLIMATE AND WEATHERING 
 
 Heavy rainfall during high-intensity storms and freeze-thaw condi- 
 tions during winter prevail in most landslide areas and provide the weathering 
 
- 11 - 
 
 Fig. 6 - Oblique aerial photographs of landslides near Illinois Valley Community College. 
 
- 12 - 
 
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 Monthly temperoture 
 
 Normol monthly temperoture based on the period 1931-1960 
 
 70 
 60 
 50 
 40 
 30 
 20 
 10 
 
 
 Fig. 8 - Climatological data from Peru Sewage Plant (U. S. Department of Commerce, National 
 Oceanic and Atmospheric Administration). 
 
 mechanism to alter the surficial sediments, the water for active erosion, and 
 the excess vater to trigger the movement. Extreme temperature and precipita- 
 tion conditions are common in Illinois. 
 
 Temperature and precipitation records for the past 5 years from the 
 nearby Peru sewage treatment plant are shown in figure 8. The solid lines in 
 both graphs represent the monthly "normal" temperature and precipitation for 
 the plant. "Normal" is based on records collected for the 30-year period from 
 1931 to i960. The dashed lines represent the actual monthly recorded average 
 temperature and precipitation at the plant. 
 
 The temperature records show that near-normal or slightly cooler than 
 normal temperatures prevailed during the past 5 years and the slopes were sub- 
 jected to freezing and thawing. The precipitation records indicate high- 
 intensity storms followed by dry periods generally have a frequency interval 
 of less than a month. This pattern of precipitation subjects the bluff slopes 
 to intermittent wetting and drying. In addition to this pattern, in some years 
 
- Ik - 
 
 these regions have periods of very heavy precipitation. Precipitation occur- 
 ring as a series of high-intensity rainfalls deluged the region during the 
 spring and summer of 1970. More than U5 inches of rain fell during the 6- 
 month period, and more than 10 inches fell during both May and September. 
 These rains contributed to the triggering of the landslide activity. 
 
 CONCLUSIONS 
 
 Slopes in the La Salle-Peru region are unstable because of a combi- 
 nation of physical factors: (l) the slopes consist of a particular type of 
 clay-rich shale; (2) the slopes are generally steeper than 20 degrees; (3) the 
 climate of the area typically includes periods of heavy rainfall. Abnormally 
 high amounts of rainfall help to cause rapid erosion of the toe of the slopes, 
 increase the bearing weight on the underlying formations, and lubricate the 
 materials in the slope, causing them to flow or fracture. 
 
 Because the type of rock is one of the major factors determining the 
 occurrence and distribution of these landslides , a study of the geology of the 
 area is essential before plans are made for construction on or near a slope 
 developed in clay -rich shale. Both ground and air reconnaissance are helpful 
 in determining and evaluating the extent of landslides. Geologic field studies 
 reveal that sliding will recur naturally. When the critical balance of these 
 slopes is upset by improper construction activity, the process of sliding is 
 accelerated and damage may be extensive. 
 
 If the existing or potential hazard of these slopes is recognized, 
 unplanned expansion of urban construction can be discouraged and disasters 
 prevented. 
 
 
- 15 - 
 
 BIBLIOGRAPHY 
 
 Allen, J. R. L. , 1969 , The maximum slope-angle attainable by sur faces underlain 
 by bulked equal spheroids with variable dimensional ordering: Geol. Soc . 
 America Bull. , v. 80, no. 10, p. 1923-1930. 
 
 Allen, J. R. L. , 1970, The avalanching of granular solids on dune and similar 
 slopes: Jour. Geology, v. 78, no. 3, p. 326-351. 
 
 Bailey, R. G., and R. M. Rice, 1969, Soil slippage — an indicator of slope in- 
 stability on Chaparral Watershed of Southern California: Prof. Geographer, 
 v. 21, no. 3, p. 172-177. 
 
 Burton, A. N., 1970, The influence of tectonics on the geotechnical properties 
 
 of Calabrian rocks and the mapping of slope instability using aerial photo- 
 graphs: Quart. Jour. Engineering Geology, v. 2, p. 237-25*+. 
 
 Cady, G. H., 1919 s Geology and mineral resources of the Hennepin and La Salle 
 Quadrangles: Illinois Geol. Survey Bull. 37 » 136 p. 
 
 Ekblaw, George E., 1931, Landslides near Peoria: Illinois Acad. Sci. Trans., 
 2Uth Ann. Meeting, p. 350-353. 
 
 Fairbridge, R. W. , 1968, The encyclopedia of geomorphology : Encyclopedia of 
 Earth Sciences Ser. , v. Ill, Reinhold Book Corp., New York, 1295 p. 
 
 Howell, J. V., 1957s Glossary of geology and related sciences: A cooperative 
 project of the American Geological Institute, Nat. Acad. Sci. - Nat. Re- 
 search Council Pub. 501, Washington, D. C. , 325 p. 
 
 McComas, M. R. , 1968, Geology related to land use in the Hennepin region: Illi- 
 nois Geol. Survey Circ. U22. 
 
 Prior, D. B., N. Stevens, and G. R. Douglas, 1971» Some examples of mudflow and 
 rockfall activity in north-east Ireland: Reprinted from Inst. British 
 Geographers Spec. Pub. 3, p. 129-1^0. 
 
 Rohn, P. H., 1969, The relationship between natural forested slopes and angles 
 of repose for sand and gravel: Geol. Soc. America Bull., v. 80, no. 10, 
 p. 2123-2128. 
 
 Sharpe, C. F. S., 1938, Landslides and related phenomena, a study of mass- 
 movements of soil and rock: Columbia Univ. Press, N. Y., Mornings ide 
 Heights . 
 
 Skempton, A. W. , 1953, Soil mechanics in relation to geology: Yorkshire Geol. 
 Soc. Proc, v. 29, pt. 1, no. 3, p. 33-62. 
 
 Smith, W. H. , 1968, Strippable coal reserves of Illinois, Part 6 - La Salle, 
 Livingston, Grundy, Kankakee, Will, Putnam, and parts of Bureau and Mar- 
 shall Counties: Illinois Geol. Survey Circ. Ul9 . 
 
 U. S. Department of Commerce, 1965-1970, Climatological data, Illinois: Natl. 
 Oceanic and Atmospheric Adm., Environmental Data Serv. , v. 70-75. 
 
 "^5 
 
 UBRahv 
 
- 16 - 
 
 Willman, H. B., 19^0, Pre-glacial river Ticona: Illinois Acad. Sci. Trans., 
 v. 33, p. 172-175; Illinois Geol. Survey Circ. 68, p. 9-12. 
 
 Willman, H. B., and J. N. Payne, 19^2, Geology and mineral resources of the 
 Marseilles, Ottawa, and Streator Quadrangles: Illinois Geol. Survey 
 Bull. 66. 
 
 Printed by Authority of the State of Illinois 
 
 Illinois State Geological Survey Environmental Geology Note 4-8 
 
 16 p., 8 figs., 3000 copies, 7-30-71 
 
ENVIRONMENTAL GEOLOGY NOTES SERIES 
 
 Controlled Drilling Program in Northeastern Illinois. I965. 
 
 Data from Controlled Drilling Program in Du Page County, Illinois. 1965. 
 
 Activities in Environmental Geology in Northeastern Illinois. 1965. 
 
 Geological and Geophysical Investigations for a Ground-Water Supply at Macomb, Illinois. 1965, 
 
 Problems in Providing Minerals for an Expanding Population. 1965. 
 
 Data from Controlled Drilling Program in Kane, Kendall, and De Kalb Counties, Illinois. 1965. 
 
 Data from Controlled Drilling Program in McHenry County, Illinois. 1965. 
 
 An Application of Geologic Information to Land Use in the Chicago Metropolitan Region. 1966. 
 
 Data from Controlled Drilling Program in Lake County and the Northern Part of Cook County, 
 Illinois. 1966. 
 *10. Data from Controlled Drilling Program in Will and Southern Cook Counties, Illinois. 1966. 
 •11. Ground-Water Supplies Along the Interstate Highway System in Illinois. 1966. 
 12. Effects of a Soap, a Detergent, and a Water Softener on the Plasticity of Earth Materials. 
 1966. 
 *13. Geologic Factors in Dam and Reservoir Planning. 1966. 
 *14. Geologic Studies as an Aid to Ground-Water Management. 1967. 
 *15. Hydrogeology at Shelbyville, Illinois — A Basis for Water Resources Planning. 1967* 
 
 16. Urban Expansion — An Opportunity and a Challenge to Industrial Mineral Producers. 1967* 
 
 17. Selection of Refuse Disposal Sites in Northeastern Illinois. 1967. 
 
 18. Geological Information for Managing the Environment. 1967- 
 
 *19- Geology and Engineering Characteristics of Some Surface Materials in McHenry County, 
 
 Illinois. 1968. 
 *20. Disposal of Wastes: Scientific and Administrative Considerations. 1968. 
 *21. Mineralogy and Petrography of Carbonate Rocks Related to Control of Sulfur Dioxide in 
 Flue Gases — A Preliminary Report. 1968. 
 Geologic Factors in Community Development at Naperville, Illinois. 1968. 
 Effects of Waste Effluents on the Plasticity of Earth Materials. 1968. 
 Notes on the Earthquake of November 9. 1968, in Southern Illinois. 1968. 
 Preliminary Geological Evaluation of Dam and Reservoir Sites in McHenry County, 
 Illinois. 1969. 
 
 26. Hydrogeologic Data from Four Landfills in Northeastern Illinois. 19^9« 
 
 27. Evaluating Sanitary Landfill Sites in Illinois. 1969. 
 
 28. Radiocarbon Dating at the Illinois State Geological Survey. 1969* 
 
 29. Coordinated Mapping of Geology and Soils for Land-Use Planning. 1969 • 
 
 30. Preliminary Stratigraphy of Unconsolidated Sediments from the Southwestern Part of Lake 
 
 Michigan. 1970. 
 h 31. Geologic Investigation of the Site for an Environmental Pollution Study. 1970* 
 
 32. Distribution of Major, Minor, and Trace Constituents in Unconsolidated Sediments from 
 
 Southern Lake Michigan. 1970. 
 
 33. Geology for Planning in De Kalb County, Illinois. 1970. 
 
 34. Sulfur Reduction of Illinois Coals— Washability Tests. 1970. 
 
 35. Stratigraphy of Unconsolidated Sediments in the Southern Part of Lake Michigan. 1970. 
 
 36. Geology for Planning at Crescent City, Illinois. 197°. 
 
 37. Distribution of Arsenic in Unconsolidated Sediments from Southern Lake Michigan. 1970. 
 
 38. Petrographic and Mineralogical Characteristics of Carbonate Rocks Related to Sorption of 
 
 Sulfur Oxides in Flue Gases. 1970. 
 
 39. Phosphorus Content in Unconsolidated Sediments from Southern Lake Michigan. 1970« 
 
 40. Power and the Environment — A Potential Crisis in Energy Supply. 1970. 
 
 41. Trace Element and Organic Carbon Accumulation in the Most Recent Sediments of Southern 
 
 Lake Michigan. 1971. 
 
 42. A Geologist Views the Environment. 1971 • 
 
 43. Mercury Content of Illinois Coals. 1971. 
 
 44. Distribution of Mercury in Unconsolidated Sediments from Southern Lake Michigan. 1971 • 
 
 45. Summary of Findings in Solid Waste Disposal Sites in Northeastern Illinois. 1971 • 
 
 46. Land -Use Problems in Illinois. 1971. 
 
 47. High-Resolution Seismic Profiles and Gravity Cores of Sediments in Southern Lake 
 
 Michigan. 1971. 
 
 Out of print