State of Illinois William G. Stratton, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Vera M. Binks, Director Division of the STATE GEOLOGICAL SURVEY M. M # leighton, Chief Urbana CIRCUIAR 134 SANDS AND SILTS OF EXTREME SOUTHERN ILLINOIS A Preliminary Report Raymond Shrode and J. E. Iamar Urbana, Illinois 1953 ILLINOIS GEOLOGICAL SURVEY LIBRARY MAY 12 1953 JLloC Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/sandssiltsofextr184shro CONTENTS Page Introduction ------ -------- i Nature of deposits --------------- 2 Mineral composition ------------ 3 Chemical composition ----------- 6 Samples -------------------- 8 Prospecting of deposits ---------- 8 Presentation of data ----------- 8 Alexander County outcrops ----------- 9 Pulaski County outcrops ------------ 12 Massac County outcrops ------------- 20 Outcrops in other counties ----------- 23 TABLES 1 # Mica content of sand ------------ 5 2. Chemical analyses of sand --------- 7 3. Particle size of samples from Alexander County ------ - 2h h. Particle size of samples from Pulaski County --- ------- 25 5. Particle size of samples from Massac County and other counties ------- 28 SANDS AND SILTS OF EXTREME SOUTHERN ILLINOIS A Preliminary Report by Raymond S* Shrbde and J. E. Lamar ; [ Introduction The sands and silts of extreme southern Illinois have . recently attracted considerable interest although only rela- tively small tonnages of these materials have been produced to date. This repdrt brings together the Survey 1 s accumulated in- formation regarding their location and character. It deals... ,-... primarily with the Upland deposits where outcrops could be stud- ■ied. . .Additional deposits -may be present -in places beneath the ; flats bordering Mississippi "and Ohio rivers and in the lowland tract that crosses parts oif Pope, Massac, Pulaski, and Alexander counties in a roughly east-west direction and is now partly :/ '•'■■■ occupied by Cache River. ■ ' •'•'The' deposits 'described are not necessarily, those most desirable for commercial development in any given area, although some such deposits' are' believed to be included. The deposits discussed are readily accessible, however j and the data regard- ing- them will serve .as a basis for further investigations 'of those areas -which; are' located near transportation -and markets and so are of greatest interest to potential producers and users of ' the sands. - - v ~- r - : : ' '; »"■' ,"- In the following descriptions of deposits those strata which Were sampled are called 'silt if, as nearly 1 as can be judged from the particle ■ size data , 'their particle size' distribution is. such that- the major portion of them falls within the size 'limits set up for 1 silt" 'by the American Society for Testing Materials, 1/ ■namely, minus' VO^O millimeters, "plus .005' millimeters. -■''. : Sieve analyses -were made by standard -procedures # Sub.-. ... sieve size fractions, reported in microns,' were -determined ; by the hydrometer method. ' ' -. ■ .':.:•■' y ~~ ' Chart correlating various grain-size definitions of sedi- mentary materials, compiled by Truesdell, P. E. , and Varnes, D. J., U. S. Geol. Survey, 1950. - 2 - • NATURE OF DEFOSITS The sands and silts of extreme southern Illinois are of various geological ages. The Cretaceous deposits are the old- est and were formed many thousands of years ago during the Cre- taceous period of geologic time. They are usually fine to very fine grained and' are commonly light colored, that is, usually light shades of gray, yellow, and cream to nearly white. As the deposits were laid down in a sea, they consist of beds of vary- ing thickness and character. Strata of clay and thin layers of gravel are associated with many Cretaceous sand and silt de- posits. .•■.'■■."■ o" ' • The Cretaceous deposits are overlain in a relatively small area of southern Illinois by a thick deposit of clay of Paleocene age which is"' the source of fuller 1 s earth near Olmsted. Lying above this clay formation in some places are deposits com- posed of strata of sand, silt, or clay. These are of Eocene age. Outcrops of Eocene sands and silts are not numerous and are known principally in the vicinity of Mounds, Olmsted, and Grand Chain. "■"' ■•■- ■■■' " : "■" "■■' ' ' Tne " Lafayette " formation is younger than the Eocene deposits and in "place's constitutes an overburden on them. It consists principally of brown chert gravel Which at many plaees has been dug for road surfacing. Strata of medium to coarse grained sand are associated with the gravel in some areas, as in the vicinity of' Fayville and Unity. Data are given on several .. samples of "Lafayette" sand. ' The sand deposits aire usually red or reddish brown due to' the presence of a variable amount of colored clay. The deposits are believed to have been laid down by ancient streams during Pliocene time. In relatively recent geological times, during the Pleistocene : epoch, several great' ice sheets successively invaded Illinois and covered parts or most of , the State but. none of them reached '" extreme southern Illinois . However :; waters • from the melting glaciers are known to have -flooded the lowlands of south- ern Illinois where they built up successive deposits of valley fill consisting Of sand, silt, and clay. Most : of the materials comprising the fill were probably carried in- from areas outside southern Illinois although some may have been derived from the Cretaceous and other deposits of adjacent uplands or from other deposits which were flooded and worked over by the glacial waters. ( The valley fill deposits are commonly gray, light gray, or brown. • The retreat of each glacial flood left large areas of the lowland- covered- with sand--, silt-, -and -clay. Wind picked up large quantities of these materials, especially silt and clay, and dropped them on the adjoining uplands, building up successive deposits totaling as much as 50 feet thick in some places al- though usually their thickness does not exceed '25 feet. The name loess .-is. applied to these, deposits. Where exposed in road cuts or stream banks, loess characteristically stands in steep faces. In extreme southern Illinois the loess is usually brown but in some, places It is , gray. .,, ,-, ... . •, ; ; Miner a 1 c pmp o s i t i on All the sands and silts of extreme southern Illinois .consist, principally. of particles of the mineral • quartz (Si02) . -White -mica j a silvery , appearing flaky- mineral ? , technically called muscovite^ and clay minerals, discussed later, are common acces- sories. . Potash feldspars, are known to be present -in small amounts in, some, of the Cretaceous' sands. The sands and. silts 'of Cretaceous • age, are not limyj neither ._ are those of, the "Lafayette" and Eocene formations. ^Some of the valley fill silts and sands. are limy but no limy deposit's are included in this report. The brown, loess is usually not limy or only very slightly so. The gray loess ' may, .be limy... . . .-. ... . ,.<..,.. All the ..samples mentioned in this, report contain clay- : si.ze material, as may be determined from, the particle size .data. In. geological usage, earth material finer than -.00^ millimeters is'-called clay. The Public Roads Administration,' American Society for Testing Materials, and' American Association of State .Highway Officials consider clay to be finer /than .005 millimeters^ and the U. S c Department of Agriculture considers it finer than .002 millimeters. J=/ As defined above, clay usually consists of clay minerals with varying amounts of minute quartz particles and possibly fine muscovite particles. The major clay mineral in several samples of southern Illinois sands and silts is kaolinite, as indicated below. It is a refractory clay mineral and is the principal component of kaolin deposits. The clay mineral illite is also found in some samples along with other clay minerals. It is non- refractory. - • • w Truesdell and Varnes, op. cit. y ■" Sample Clay Minerals In Clay. S 1 ze- Fraction NF k67 '■■ . ' Chiefly kablinite, probably 75 percent, plus • w h62, 3, ** ' ; ; " " . : , n '■ ' " : .;.;';' .! "' :■■■: ■• NF 309 '." " : About 5Q- to 60 percent kaplinlte', with .MD to *' "' * ' 5 Q percent clay micas' NF k70 35 to 50 percent kaolin'ite, remainder illite NF ^69 35 to 50 percent kaolinite with illite and/ or r; montmorillonite ■ Nearly' all the Cretaceous 'and' -Eocene sand samples' in- vestigated -contain relatively numerous' -flakes of white' mica but this mineral is rare or.absent" in the ,, Lafayette M -and valley- fill f deposits* ■ The actuai/^ercentage 'of muSc'ovite in the' samples is considerably- less than'-the abundance :; of the mica flakes suggests. ''Tests, made'- on a sample : of k-8 by 65'.. mesh sand showed that ^-00 mica 'flakes sorted from this sample weighed about* the' same' -as 100'- sand ' grains from the same' : sample f ' ' ; ' ' '' " . : • ; ,: . : Table 1 contains data on the estimated weight -percentage of mica in the plus 3?5-mesh portions of three of the more micace j -ous samples. The figures are based on counts of 300to 500 sand , -grains and were converted to' weight percent by the experimentally determined weight ratio. mentioned above. '.'The presence, of an 'appreciable percentage Of mica' in' all-size grades •'' examined' is , significant in' any ; processes attempting to; produce mica-free sand ( or to. recover -the mica from the micaceous sands. y Pe 20 percent jj *•••'■■ Identifications by W. A. White, Illinois Geol. Survey, 1953. Percentage figures are estimates and may vary. as.. much as... 15 „t a,- Fable 1. - Mica Content of Sand Weight, percent of : "Estimated mica Estimated mica content of content - Composite sample size fraction — weight .percent of samples Mesh retained weight percent of entire sample 65 ■ 0.1+ 96 oA 100 6,6 ' 15 1.0 NF 308, 309 150 18.6' 5 0.9; 200 28.7 3 , 0.9 270 9.2 2 0.2 .325 7.5 ■; 2 Total 0.2 3.6 KQ 3.1 96 3.0 • 65' 5.5 2 0.1 100 7.1 ' 2 0.1 NF h67 9 ^68 150 6.6 ■■•'-:: 5 0.3 200 21+.1 2 0.5 270 • 12,5. '- '1 0.1 •325- ■10.7 7 3 • Total ?'?> AA ^8 0.6 59 0.^- m 5.7 ' 3 ; 0.2 100 28.1 ' '.:- :..:• lf 1.1 NF ^i-62, ^63 150 i 27>8 . '1 0.3 and A-jSk 200 2^.2 2 0.5 270 5.1 . 2 0.1 325 .••-3*3. ■ 3 Total 0.1 2.7 In addition to the above, grain counts were made on the sub sieve; "fraction of a composite of ... samples' NF 308-309. The counts -are hot'- -highly accurate because the particles were so small but they give estimates of about 5 percent muscoyite, in the minus 325-mes'hplus lO^micronit/ size grade and about 6-g- percent in the 10 by 5 micron fraction.!!/ w 10 microns equal about . OOO^f inch. Chemical. ..compos it ion :■- ;• : "- " "■ "■"' Table 2 gives the chemical analyses of four sands of Cretaceous age and. one sample believed to be valley fill of. Pleistocene age. In order to provide' information relating to Various, .size grades that might be produced commercially by processing the sands, the samples were classified into two or three - size- grades. Each size grade was analyzed separately. Size classification involved agitation in water for 10 minutes in a mechanical stirrer, followed by wet sieving, then grading by settling in water. . The potash (K2O) shown in the analyses is probably due at least in part to the presence of white mica (muscovite) which contains about 12 percent potash. Potash feldspars containing about -I? percent K2O may also contribute to the potash content, Muscovite also contains about 39 percent alumina (AlgO?) and the potash feldspars about 18 percent, which may account for part of the alumina in some of the sand samples. The minus 10-micron grades of the samples contain all or most -of the clay present in the original samples. The high alumina and potash content of this grade is due entirely or in large part to the presence of clay minerals. These minerals may also contribute to the potash content of some of the coarser grades- of some samples wherein a small amount of clay may occur as iron-oxide cemented grains which were not completely destroyed during the mechanical stirring which preceded size classification. The titania (TiC^) reported in the analyses of the plus 10-micron. size grades probably results from grains of the titan- ium-bearing minerals rutile and ilmenite, . These mineral grains are evidently very small, because the highest titania values for the Cretaceous samples are found in the minus 325-mesh plus 10- micron size grades. ".The mineral anatase ? also titanium bearing, may be responsible for most of the titania in the minus 10-micron size grade. Anatase is often found in minute particles in clays, in- cluding the kaolin at Anna, Illinois, 2/ which is believed to be of Cretaceous age as are many of the sands herein reported. 17 Analyses by L # D. McVicker, Illinois Geol. Survey. 2/ White, W. Arthur, personal communication, 1953. R 2> 9 9 9 ooooo 2 on o o q o o o c c rH H rt r-l r-\ r-\ H r-{ H - 7 ON H O ^ONVO H^NHIA SO cm CM £ H r-\ r-\ _4 On . H rj CVJ CM P^ £- SO O H On CM CM On <"°\ Os SO Ox -J" ^t r 1. C « C 2 '. f 'i°i-^ OO.HO.H . CM-^o'T^"? rH H r-» ^ rH ,_j *';.'*'* H *'* " * HOH OHO : 00--JOO OOHOO JD t! ^ ^ H< S CM UN m CM -4 ISOfllf\C«- CM rH H OOJO HOC-HH- HHc^HrH Ojrr\rp us Os so Onco Oco -J- CO CM C- _rf ^ ^ ^ -; -°i °i ^ irri=-H po H h ™ which show particle-size distribu- tion. Sieve-size data were determined by standard procedures. The data given for many samples on the size distribution of: the subsieve size material (reported in microns) were obtained by the ; hydrometer method or by settling and siphoning. Some of the samples of fine or very fine sand contain a small percentage of material retained on the coarser sieves and consisting of particles' of sand and silt grains cemented by 'iron oxide. The quantity of such aggregates is less than .3 percent and commonly less than 1 percent. ALEXANDER COUNTY OUTCROPS Samples NF h§2 to 1 +66 . - ,T. 15" S., R. 3 W. , sec. 3 1 *, NW 1/h mi 1/^ SE . 1/4 , ne ar Fayville . Sand pit in river bluff on east side Missouri Pacific Railroad. Cretaceous sand and silt. ■•.;■. ,;.k , ..'■ ..: ,»■■■ ■ « '.; ; : . ~ •■■ Thickness Feet ....-• • \ 7. Loess-,, brown. ■* ,5+.'. ■'..: Di Silt, dark gray,, clayey, micaceous; Sample NF *+66 • ; '" 8 5. Silt, gray, micaceous j Sample *+65 7 ,, ; ..; ; H-. Clay, dark gray J+i "3» Sand, fine grained, micaceous, light colored, upper 2 feet yellow; Sample NF k6h ' . .:.-■-■:• .< : ♦ ■;■' 8 2. Sand, fine grained^ 'micaceous *, f light.; colored, : lower 2 feet pinkish^ ,' : Sample' NF *f63' '•- '''''.■" ' ' 7 1, Sand, fine grained, micaceous,' light colored; Sample NF ^62 11 Covered Sample NF 300 . - T. 15 S., R. 3 W. , sec. 3^' * : lA NW U/h' NVTlA, near Fayville. Sample ,NFv3 00 from 35 feet of light colored, micaceous Cretaceous sand exposed in cut along old roadway between Miami and Aetna Hollows. Overlain by 25 feet or more of loess. Sample LM 29 and Sa mple j+1 . - T. 15 S., R. 3 W. , sec. •3 1 f, NW 1/h m 1/4- SE 1/4- ', near Fayville. ' Two samples taken at different- times from a small sand pit along the road and just east of the Missouri Pacific Railroad crossing. Their vertical- relationship is not- 'known. Sample LM 29 was taken from 15 feet and sample" 4-1 from 20: feet of. light colored, micaceous Cretaceous sand.' • .• '..-'* - 10 - Sam ples 42 and h?.k . - T. 15' S., R. 3 W. , sec. 3S near center E 1/2, near Fayville. North and slightly east of Fayville a reddish colored "Lafayette^ sand forms the core of the upper part of a .ridge.;, its shoulders are covered by brown chert gravel.; Sample ^2A was taken from 17. feet of exposed sand and sample 42 from the upper 6 'feet of the' same outcrop. •■■'. ;: • Samples, hj and 46 . - T. 15 S. , R. 3 W. , sec. 3>+, NW l/h SE 1/4 NW- 1/4, near Fayville. Cretaceous sand and clay from an; exposure in lower Miami Hollow north' Of Fayville. The beds dip 30, degrees northeast. The deposit may be slumped. "<;•• , [-.'• Thickness ••:.':: ■"■■■ '"'. " ' I Feet Inches h. Play, gray ' ' 15 3. Sandstone, iron cemented , o 2. Clay, var legated ; Sample 45,/., 6 1. Sand, micaceous, variegated;:. ; Sample hG . • -i / .-.•: 9 Covered v SanmlesJf7."and>8 ..- t/ 15 S., R. 3 W. , sec. 3 l H, SE lA NW lA W 1/4,' near Fayville. • • ..' - ... .,..:,'. Exposure on east side of cut along the Missouri Pacific ; . Railroad north of Miami Hollow. Cretaceous sand. ► '•: ;r ' ■ ! ":- " Thickness Feet Inches • : 7. -Loess •: *■■■- .'■'■ -■>):. 7 6. Clay, purplish gray. 1 •. \ ".'/ "..' / 4'-" ■%"■■' ;. 5. Gravel, black and white chert 3 ' . \' h.- Sand, yellow, ' interbedded with gray -'-.'••••••-• '■■■■ clays Sampled ■.?•.; .-, "■", : -".* '3. Gravel, black .and' white, chert •• ^. ; - . .2 • J •' ; ; / 2. Sand, yellow -and white; -Sample 48 ... ■ ;, 2 . ... .6 1. Clay, yellow, sandy ■; .;.,:.'•.- f . - ■•■ . . - Covered - 11 - Samples 50 and 51 . - T. 15 S., R. 3 W. , sec. 36, NW 1/k NE 1/k SW 1/M-, near Fayville. Sample 50 from about *+ feet of yellow Cretaceous sand exposed at the east end of a hill about two miles.. east of Fay- ; ■ ville. Sample 51. from about. 9 feet of whit e : -sand- at- 'the wes;t end of the same hill. ' Relative stratigraphic position of samples not known. Sample 55 . - T. 15 S., R. 3 W.,- sec. 28, SE 1/k NW lA I 1/k, near Fayville. Along the Missouri Pacific Railroad, about one mile south of Rock Springs trestle. Cretaceous sand. .. ; , .■ ■. Thickness ■ , . '. . V' Feet 6. Loess '.;:"; . ;;. 0-2 5. Gravel, brown rand, white' chert' - ; ''•.'; " .' . 2-g- k. Sandstone, v ir on 'stained ,: ; ; -.;■.'" i - 2 3. Sand, red; Sample 55 .).' '"•'..'. ..'..,• 15 2. In descending order, beds of conglomerate, clay, chert and talus 13 - 26 1. Limestone 6 ■•-Covered , • '" . -• •^• ; r~'''''" ; " r '' ' , ■ Sample 6l . -, T., 15 S.. , R. 3. W. , sec. 27, NE 1/k NW 1/k \. near Fayville. , -- ■■;■.■,= .North -of Fayville in a hill on the south side of Rock Springs Hollow there is exposed 16 feet of red "Lafayette" sand, Sample 6l. Under the red sand there is an additional .1.6 feet of sand, silt, arid clay which was not sampled. Sample NF 269 . - T. 15 S. , R. 3 W. , sec. 16, NW 1/k ' NE 1/k NW 1/4, near Thebes. - . \> , . ■-•'■;• ,*"- /•;_, ' : '' ' . . Sample NF 269 from 18 feet of brown ioes's along Illinois route 3 about 1/2 mile east- of Thebes'. ■ ■ * 'y\'. "■ \i Sample DS-*f . - T. 15 S., R. 3 W. , sec. k, M'l/k SE 'l/k : NW, lA, near Gale. Sample DS-J+ from ^8 feet of brown and gray calcareous loess along the Missouri Pacific Railroad about 1/2 mile south of Gale. • - 12 - : ? - -PULASKI .COUNTY OUTCROPS, , ., ..^ Sample's- NF +79- ^80 n +86 . -T. 15 S. , R, 2. E., sec. 2, NE 1/+ NE ■.■1/4-,-SW l/M-y near;' Yates Landing.., Outcrop' on east bank, of Post Creek cu.1>-off about' '150 yards west of Round Pond School, on the north 1 'side of ah a band one road. Sampled in 1952, Cretaceous sand and silt. • ■':■■?' •' ;:: --' .''■■ , , o ;■ Thickness '"' ,'• .. •-■-■ -Peel ''-.-, '"'6". ■'", Loess ' " ; '. ; :' ■ ..,-• 20 ± 5. "Sand* red, mixed .with, loess, .-- ,,, ', ;;' . .2 .■.-v.., 4, Silt, micaceous, light gray, firm§ " '■ '■'■■ Sample NF +86 2 3. Sand, micaceous, reddish, firm 1$ .., n 2 B Sand, micaceous, white; Sample NF +79 16 1, Sand, micaceous, white, top .6 inches '- '. clayey; Sample NF .1+80 _.-,,', / 5£ Covered by slump from above, , .. '■'. ' Samples NF 30+ and 306 . - T. 15 S. , R. 2 E.,, sec'. 2, NE 1/+ NE 1A SW 1/+, near Yates Landing , . " _ . ' v .; • Same location as above but in ditch on south side of 'iPpad and sampled in 1935. Cretaceous sand, * ' '"- " Thickness ■; •■;- . ;, ,. ty -. ., _ r ■• - Feet - "• ; .- 8, Loe^s ' '■ / "^ .-''/-, r , „. 7-10 7v Sandy clayy' 'micaceous, .• reddish brown " : \ ;; + : 6 . CI a-yey ' 's and , :■ . mic ace ous; , red, or , ,.. ..*::'.;' • ' .'• • : orange •' U: + - :.:\r .. . .5.- Sand, micaceous, variegated, with thin ■■ Clay partings;,. Sample :NF 30+ ,.--,, .12 + . Clay, white >; ! : v_ ,; --"-'. ~~ -,=; :V 2..i 3. Sand, white with thin yellow bands • , -'l5'' 2. 'Clay, "white , : . .. 2 1, Sand, white- 'with bands of yellow* ; Sample NF 306 13' •i\ ■ , Covered - 13 - Samples 79 and 80 . - -T. 15 S., R. 2 E, , sec. 2, NE lA NE 1/h SW -1A, near ! Yates Landing. «■• ... ' . . •- Exposure along Post Creek cut-off near the above two mentioned exposures. Sampled in 1927. Cretaceous sand. 7. Loess , 6. ... .Gravel, chert -. . -. .: . .:■. .... ... ..;§"> Z '\ 5. Sand, yellow, lower 3 ft. light gray, micaceous 5 Sample 79 12 h. Sand, .clayey, white to pinSJ' micaceous Jh 3. : Sand, mostly white, some yellow, mica- •.'''. ceous; Sample 80 <■' r > -k[1 >* r. -. ■■ 17 ' :: 2, Conglomerate and some gravel ; 2 .- ■ 7 1. Limestone, dark gray 7 , Covered Sample NF *f8l . - T. 15 S. , R. 2 E., sec. 2, ,SW 1/h SE 1/h SE lA, near Douglas Landing. ■..«"■' Sample from h feet of micaceous, light yellow Cretaceous sand with bands of reddish clayey sand in the bank of Ohio River about 1/h mile upstream from Douglas Landing. -' : Samples NF 1*93. k9h.- jj95 . - T.- : lk S. . R. - 2 E. 9 : sec. .#+, SE 1/k SE 1A SW 1/4. i ^~ •■ •' , .' : "-; Exposure about three miles east of Grand Chain near the top of a low hill. ' Cretaceous (?) -sand. , 5. Loess. ■' Sample NFA-9 5 - • " ■'-'■ ' ■ -:■'<• 10* h. Gravel, brown chert • . 1 - 3. Sand, Ted with yellow bands, slightly . micaceous ; with thin clay band s . ' • Sample- NF k9k ■'■: ? • : ■ . :' 3 2. - Clay, yellow - 1 1. Sandy' micaceous. 'Alternating bands of •ireadish yellow and pinkish gray bands. . t Yellow bands have coarser material and more mica than- -the pink. Sample NF ^93 . Exposed 3 Covered - ih - Sample 77 . -'t.' 15" S., R. 2'e,, sec. "V, ' SW lA SW lA SE lA, near Grand Chain Landing. ■Sample from 7 feet of clayey, yellow Cretaceous sand in a north-south creek along the road near Grand Chain Landing. The sand is underlain by clay and overlain by 3 to 5 feet of brown chert gravel and thick loess. S amples NF ^82 and 1+37 to V?2 . - T. 15 S., R, 2 E., sec. 18, swiA w i/.m- sw iA. For over half a mile downstream from Dam 53 along Ohio River, Cretaceous sand and silt is exposed in varying thicknesses. Section described below is located about 500 yards downstream from the dam. Sampled in 1953. : • ' Thickness Feet \ -,10'. Loess, brown . r . : . .....•'. ../.M"?^ 9. Sand, micaceous, ' red at/top grading to reddish yellow toward the •• - r ■ bottom. Abundant;! clay bands up - \.to li- : inches thick at top decreas-- :.. ■■■■■■ ■ ing in number- and thickness : down* ward. Sample NF h&7 from lower 12 feet of sand 12-18 J- , 8. Sand,, yellowish- red 2 micaceous. Base ■.,,.,,.. marked by iron-oxide cemented!, sand. . Sample NF ^-88 ? 1 ■• 7. Sandstone, yellow-gray ••-..:...': 2 6. : Silt, /white -to gray,. Slightly micar ;■} ceous, very fine. Sample NF M-89 o 5. Silt, white, micaceous, firm. Sample NF 1+82 7 k. Silt, light gray, very fine, clayey. or Little mica. Sample. -W ^.90 .. H- "-" ; 3. Covered -,. .:,'.. ..;■: .. • :. , 12 2. Silt; yellow and' gray bands, rela- .-.'' tively coarse... - Sample' NF M-91 2- a - 1. Silt, clayey, dark gray, mica present in bands along., bedding plane 3.5 con- tains nodules, of pyrite and iron- oxide cemented materials. Sample NF ^-92 !5 Covered. River level . Samples NF' 316, 317, 3l8 .'- T. 15 S. , 'R. "l'E.; 'sec, 13, : 'SE lA ' NE' 1/4- SE lA, near Dam 53 . . Exposure 'in river bluff slightly farther downstream than the- section described above. Sampled in 1935. Cretaceous sand and silt. '"■ r.::.-:)>J Thickness . ; KOX . , ■ r. ; . ;; : A ;,-.; • r ■ ! , .•; • ■■-■> C- ' ■■ i ~ ^ feet .,^5. Loess"'- ■''.' ./';'" ," r V\ / ^-.'-. .0.5-20 M-. Sand, red', clayey; ' Sample NF 3 18 : : 8 3. Sand, micaceous, • yellow : and whiter, v. . ■' S'ample W 3i7 ' ' ,. J ' , ' . 8-10 2. Silt, fine, white, ... micaceous «. : Sample .■• ;3WX316' - ' "' ; ; *-'; • .: ■}.■: 15 t Covered -.-'i-jvo* 1 1. Clay, dark, micaceous, pyritic, with partings of sand 10 Covered , r : ;- Vj* „? - *,'!...' .-. : --'- -"•-"••• : '- Samples 69 and 70 . - T, 15 S., R.. ; 1 W. v sec, .13, i :.Sfefc 1/^-NE lA SE 1/M-,, near Dam 53 » , , i ' . " * '; This exposure- is j somewhat further downstream from Dam 53 than the above two locations. Sampled in 1927. Cretaceous sand and r.s.ilty clay. as Thickness . ......... -v, s •"• Feet 6. Loe&s v ' ; ; '.''.■'. ' '■ ■ ' 5-25 5. Sand, red : at' top to yellow at b£'se$ . Sample 7P ,, V) i y .• ....■' 25* *+. Silty clay, white.; Sample &9 ■ <> , :•' • 12* 3.'i ; . Silt, white, micaceous., with iron- oxide'- concretions' 18* 2. Silt, yellow, with, iron-oxide ce-ment 2 -""3 1. Clay, gray-black with 1/8 inch layers: of mica along bedding 12 Covered - 16 - Samples NF 313 to 315 . - T. 15 S., R. 1 E. , sec. 26, NW lA NW 1/4 NE 1/4, near, 01ms ted, ••• .'... Section exposed along east side of the creek along the secondary road leading to Caledonia Landing. Cretaceous sand. Thickness Feet 6,! Loess 10-15 5. ' Gravel, brown chert 1 h. Clay, yellow to dark gray, gritty 6+ 3. Sand, clayey, glauconitic, gray; Sample NF 3I5 6 2. Sand, micaceous, with clay, yellow: Sample NF 31^ 8 1. Sand, micaceous, light yellow, fine* Sample NF 313 3+ Covered Samples 72 to 7h . - T. 15 S., R. IE., sec. 26, SE 1/4 NE 1/4 NW 1/4, near Olmsted. ....> . Generalized .section .?.a .little southwest of : Caledonia Landing and from 300 to 500 yards downstream from the locality described above. Cretaceous sand and silt. • ■=-- • ' ■ ■■■ Thickness Feet ' ' ; -.,-o 6.; Loess * ."5. 'Sand, yellow, micaceous, glauconitic; Sample 72. Sample 73 was taken from 6 « :■ the same bed a short distance to the south, „ ,. h m Sand, yellow, cemented with iron oxide 2 '•.\ 3. Silt, clayey, gray, micaceous ■ -11 2, Sand, -yellow, .micaceous with' thin clay ■■" ..;•'.!- "bands "■...< 8 "...I* Clay, white, . micaceous.; Sample 7^ ■ « .*+ Covered ■ . '. ; • . Samples NF 422 and 423 . - T. 16 S. , R. 1 W. , sec. 15, ^E 1/4 NE 1/4 SW 1/4, near Mounds. Road cut at west end of Mounds overpass over Illinois Central Railroad. Eocene silt. - 17 - 6. 3k>ess , ,■{ ,*.:•■; I ,'m ■• 5. pravel, brown .. ,clwk \o ' • ; ";• - ] +. "Sandy clayey, ,red ; and yellow. . ' 3. Sand, fine' and clay interb'edfted 2. Silt, light gray r locally yellow ... r al orig j o i-nts', ' in pla ce s c onta ins . ' « . ■■ ; • black organic material; Sample • ...t<>^ *NF 1+22 1. Silt, clayey, gray locally contains black organic materials Sample r,r ' / •.<< ..: Jil j... :-• '-.- NF !+23 ... r ,ji /. '•' ; .- *»• " , .V::'^".TEjf. ;:' , " v ■ "" ;sCoyerqdl<" • " ,; ; * »;■■■■•. neafMounds: T '^ 6 ^V"^ r l W.,'sec. 15, SW 1/k m 1 A SW lA, Exposure :ii£;& series of gravel pits in a southward- rpntvf/pffL^!^-? 6 ^ ° f t ?f overhead br ^ge across the Illinois central tfailroad at the northwest corner of , Mounds, . "Lafayette' 1 \ij sand. ,„ : • '. , -.•■'•'.■■ '. . ■'• . .•• -•■■ Thickness ; ,.;•"' Feet 30 ^. Loess., brown to gray 3. Gravel, bronze chert, interbedded with lenticular white, yellow and red sand ; Sample 90 is .from the sand '•..- ; ■ '• 5-15 2. Clay, silty, buff and pink 3 *; 5 1. Clay, buff gray, to black (POrter *s ■ -or Creek, formation) • '" 6 Covered. • ' v Hfaf^vTIIa Rid T ie" 6 " S - rR: * W " B6C ' 3 > SE lA SW ^ «E lA, 1L ^ 5 Xpos ^ e ne , ar middle of the Illinois Central Railroad cut through a ridge about 1/2 mile south. of Villa Ridge. "Lafayette" (?) sand. . 18 - Thickness Feet . ";;,.$; Loess 30* k. Iron stained zone 2+ - 3.. Loess, grading into bed below 12* 1 - 2, Sand, red, cemented by, iron oxide; Sample yl. Bed has 1 to 6 inches of bands of brown and white chert gravel; not included in sample. 10 - 15 1. Gravel, bronze chert, moderately cemented 8+ Covered Samples NF \08 and ^09 . - T. 15 S., R. 1 W. , sec. 31, SE lA NE 1/M- SW lA, mear Unity. Outcrop in farm yard about li miles northeast of Unity. Cretaceous silt. ■-■'•*' Thickness Feet 3. Loess 15* 2. Silt, clayey, micaceous, white, with yellow ferruginous nodules 5 Sample ; NF 309 10 1. Silt, micaceous, sandy and clayey, grays Sample NF 308 > 5i Covered . ■"■".: Sample 76 . - T. 15 S. , R. 1 W. , sec. 31, SW lA NE lA SW., 1/M-, near Unity. Exposure in the east bank of Cache River northeast of Unity near the outcrop mentioned above. Cretaceous sand. Thickness < Feet " h. Loess 20* ,3. Gravel, . brown chert- 1 - "% -■■'"■■ 2. Sand, white, micaceous, with '■' r 'ferruginous concretions; Sample 76 ? 20+ 1. Silt, in river bank h Covered - 19 - Samples 3Vand 3*r .--^TT 16 S., R. 1 W. , sec. 7," SW lA NE lA NE 1/4, near Unity. In a stream bank about 1 mile southeast of Unity. Cretaceous sand. •■■""'■'' '■-■ thickness Feet .-'■' k. Loess" ■"-■■. ,-:''V'iL'i -■'3 + 3. Gravel, white and brown chert 1 . ", .. . ' . . 2' . S and , mic a c e ous , whi t e 5 Sa mpl e 3 3 *+ .... .1. Sand, micaceous, yellow; Sample 3*+ 5 Covered Samples -NF 496. 1+97. **9'8 . - -T-J: 16.S,. R. 1 W.', sec. 7, SW 1/4 SW 1/4 SW 1/4. : ■■ - ; ' . Exposure of "Lafayette" (?) sand in abandoned gravel pit in the east bluff' of Cache Kiver about li diles -south of Unity. -' ' "" : Thickness - ■• , * -' .■;.- - .:; ,^ ; , " ^ » . 'Feet 3. Loess, calcareous. Sample NF ^-96 from the lower 20 feet, total 'a •'■■•.' >Li •■•••■*i±hic]oies^ ? »- '- <■■- ■- <^ : -.^z •'.„.•.•.• _:3'0&UJ"''' :: : '' ; 2. Gravel and sand. Sand is present a s : ..'. ""■••!' a nearly continuous layer 2-g- feet ~- : '.' '. "■-'< • - f .- ■■■.'. '/'•.*"■ 'thick near' the base of the -gravel. ' - ■:■■ -Sample NF'^97 : is^ from thi^ sand, . , ,;■=.= : ,• Total thickness of gravel . :■ '& -'18 - 1. Sand, white to gray, coarse; ;.;;•.'.:;:;,:. Sample W i+98 3 Covered Sample 212 .: - T. 15 S., R. 1 W.,' sec. 15, NE lA ; S w lA, near Pulaski. ?.:*.? ". . ' ' . '"." »\ •• ." • ,'"■-' Outcrop just south of Pulas-ki, - ! Cretaceous, sand. >'■-' ,■•:■-• -•.••i'- •■/,■:. . ; '. ? jI.xS Thickness " ■■■• '"• '. "''" r ' Feet 7. Loess • •!.'■ V 20* .•*■ ■ 6, Gravel, brown and white chert 1-7 5. Covered' ■..-■=" >■■'. •-.„■:< uu 1*5-20 A. Clay, gray : - , .■•' 6 3. Conglomerate, brown- chert ; • :•■ . *J ■§■ '2. Sand, yellow-; Sample 212- ■ ,•---"■'•• 6 1. Sand, micaceous, clayey '-;-•. 1. :'■ 5 Covered 20 - .;.;-'. ? ' v ' MASSAC COUNTY OUTCROPS Samples NF ^67 and H68 . - T. 15 S. , R. k E., sec. 11, SW lA NE lA NW X/H-5...'neap Round Knob. Outcrop in railroad cut along Illinois. Central Railroad about 1 mile south of Round Knob.' Cretaceous '.sand and ,silt. '•■ Thickness Feet 6. 5, 2. "iv Loess S and ? . yellowish red >. ." "' *■■■•' - ; C over ed : , ' probably fine sand Sand, white with a few yellow bands and some limonitic concretions ;.. . ■■" Sample NF k6? '''■■•• Silt, yellow and white, a few limo- nitic concretions; Sample NF *+68 Sand, yellow, poorly exposed. .^Estimated Xlay, gray, 3 feet partially covered Covered - :;:: ' 7 '- ' '',' - m 5 - 6 Samples NF 322. 323. 325 . - T. 15 S., R. ^' E. r sec. 11, NE lA SE 1A NW 1 A, near .Round Knob . . ■ . • Exposure *along -the ; cut'of; the niinpis Central Rail- road, about lA mile south of the above location. Cretaceous sand and silt*. >-.-. 8. Loess, gray and. buff ■■'■ - • 7. Gravel, brown chert 6. Sand, clayey, red, firm, grains iron-oxide -coaled * 5.* ; Sand, yellow-orange; Sample NF 325 from lower 6 feet ^iV'Silti light colored, micaceous, , with thin clay streaks; Sample . NF 322 from the lower 7 feet and r- NF 323 the upper 5 feet 3. Clay, gray white 2, Sand, orange, yellow, and tan inter- . beaded. Some clay veins 1. Sand, mostly white and yellow, some brown, numerous clay beds Covered 12 - 15 12 - 21 -.., k .. .,;;.._,...;.:..- ....... Samples NF *+72 and 1+73 . - T. 15 S., R. VE., sec. 2, SW lA SW 1/M- SE 1/4, near Round Knob.. , In the '■ road cut along 'the west side of the black top about 1 mile south of Round Knob. '"' ■-•■;:;'; Thickness Feet ■; : \'-'.h+ 6' -""12 I: 3. 2. : jv 3... Loess Gravel, brown chert • Silt, clayey, reddish Silt, light gray and yellow. This bed is probably Cretaceous; Sample NF V73 •'■.'■•,/■.,. • ' Sand, light yellow, micaceo'us. Cretaceous sand; Sample NF h^2 Covered Samples NF V70 and V71 . - T. ih S., R. ^E.," sec. 23, NE.l/V. SE 1/4-' ME lA, near Round Knob. Exposure in west side of Rineking cut a^ong Illinois Central Railroad northeast of Round Knob about 3 tiiles .north of Round Knob. Sampled in 1952. The sampled beds are believed to be valley fill. :•',"' ■ • ;■ I ..'/J: Thickness Feet 6. Loess 5. Sandstone, a discontinuous layer of blocks up to 1* x 1' x .5' h . Clay^ reddish' brown' 3. Sand, not bedded, yellow and very light grav$ Sample NF h-71 2. Silt, clayey, stratified • Sample NF k 7 1. Sandstone, thin bedded, micaceous Covered 12- ' 8 •- 22 - Samples 9^ and ,95 . - -T. 1^ S./R, k E.," see. 23, NE 1/k SE 1/1+ NE 1/M-, near Round Knob. • ■ Another outcrop somewhat north of the above exposure was measured and sampled in 1927. Valley fill (?) sand. Thickness Feet h. Loess 11 3. Sandstone rubble and brown clay 5 2, Sand, pink and yellow; Sample 9k ' 13 1. Sand, clayey, white; Sample 95 ' 13 Covered Sample NF h7h a - T. 15 S. , R. h E. , sec. 7, SE lA SE 1/1+ SE 1/"+, near Choat. Exposure in cut along the Chicago, Burlington and Quincy Railroad about 3A mile north -of Choat, The cut is much slumped. Cretaceous (?) silt. Thickness Feet 5. Loess 6 ' H-, Gravel, brown, and red sand 2 3,' Silt, light gray; Sample NF 1+7*+ 9 2, Limonitic layer, 2-8" 1. Sand, yellow, cemented irregularly with limonitic, material ' 3 Covered Sample NF If 69 , - T. 15 S., R. k E,, sec. 27, NE 1/k NW 1/1+ SW 1/4, near Choat. Sample NF 1+69 from an outcrop of 8 feet of yellow and light gray silt exposed along the east side of the paved road 2,9 miles south of Choat. The silt is not micaceous and is prob- ably valley fill. OUTCROPS IN OTHER COUNTIES ' ' :j Sample NF 26*+ . - T. 13 S., R; 6 El," secv^, S 1/2 S 1/2 NE lA, ! near Golconda. " • ' ']""" ; \: Sample NF 26^ from '20 feel of loess; exposed a% the 'north edge of Golconda along State Route 3^ ib. Hardin County. Samples ^ §nd\ . - T, 12 S., R. 2 W. , sec. 35^ E 1/2 SWilA SW 1/4- , near . Kaolin* ( .; :" ; * • - ■•.;*'■! Sample 3 from a pocket of yellow sand .5 feet thick in the northeast corner .of a now. abandoned "kaolin pit, at Kaolin Station;. Sample V from 20 feet of orange and red sand in the. north wall of an old clay pit at the same place. Deposit is Cretaceous (?).• Union .County, •""•'• • : * lj a -P l co O a h o ?H •H S- 1A CM "LA . 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