This paper is the result of an attempt to determine, if possible, the relation of the Wisconsin drift to the Iowan drift, not only along the immediate border of the Wisconsin drift, as outlined in the Iowa State Geological Survey Reports, but within the Wisconsin drift plain itself. A careful and detailed investigation was made along the eastern border of the Wisconsin drift from the northern boundary of Worth County, where the eastern edge of the Wisconsin drift enters the state, as far south as Hardin County. Examination of drift cuts, well logs, and a recently excavated coal shaft, located in Hardin County on the border of the Wisconsin drift, failed to reveal, in any positive way, the presence of Iowan drift beneath Wisconsin drift

Cable, E. J.

English

University of Northern Iowa

Proceedings of the Iowa Academy of ScienceVolume 25 | Annual Issue Article 501918Relation of the Wisconsin Drift to the Iowan Driftas Revealed in Worth CountyE. J. CableIowa State Teachers CollegeCopyright © Copyright 1918 by the Iowa Academy of Science, Inc.Follow this and additional works at: https://scholarworks.uni.edu/piasThis Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion inProceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contactscholarworks@uni.edu.Recommended CitationCable, E. J. (1918) "Relation of the Wisconsin Drift to the Iowan Drift as Revealed in Worth County," Proceedings of the Iowa Academyof Science, 25(1), 539-544.Available at: https://scholarworks.uni.edu/pias/vol25/iss1/50RELATION OF THE WISCONSIN DRIFT TO THE IOWANDRIFT AS REVEALED IN WORTH COUNTY.E. J. CABLE.0This paper is the result of an attempt to determine, if possible,the relation of the Wisconsin drift to the Iowan drift, not onlyalong the immediate border of the Wisconsin drift, as outlinedin the Iowa State Geological Survey Reports, but within the Wisconsin drift plain itself. A careful and detailed investigationwas made along the eastern border of the Wisconsin drift fromthe northern boundary of Worth county, where the eastern edgeof the Wisconsin drift enters the state, as far south as Hardincounty. Examination of drift cuts, well logs, and a recentlyexcavated coal shaft, located in Hardin county on the border ofthe Wisconsin drift, failed to reveal, in any positive way, thepresence of Iowan drift beneath Wisconsin drift. Many instancescould be cited where unquestioned Wisconsin drift was foundsuperimposed upon, (a) Yarmouth deposits and, (b) Kansantill. One of the best exposures along the Wisconsin drift bordershowing the relation of the Wisconsin drift to the underlyingdrift, is found along the south bluff of Lime creek, southeastquarter, section 35, and south one-half of section 36, Fertiletownship, Worth county. Lime creek, in this particular locality,is cutting on its southern bank into a high bluff of Wisconsindrift and affords the following section :SECTION ALONG THE SOUTH BANK OF LIME GREEK, FERTILETOWNSHIP, WORTH COUNTY.FEETE. Sand and gravel, largely sand near the top and more gravellynear the bade; many of the included pebbles are covered witha coating of iron oxide 161Cable: Relation of the Wisconsin Drift to the Iowan Drift as Revealed inPublished by UNI ScholarWorks, 1918540 IOWA ACADEMY OF SCIENCE VOL. XXV, 1918D. Grayish brown calcareous clay, somewhat jointed, highly ironstained along the joints; grading into (B) rather sharply.... 20C. Yellowish gray clay, highly calcareous; contains small bowlders, and grades gradually into ( D) 20B. Yellowish gray clay grading into bluish black jointed clay beneath ; highly calcareous 30A. Dense, fine-grained bluish black, jointed clay; contains smallquartz pebbles and pieces of wood; is highly fossiliferous; tothe water's edge 2Horizons B, C, D, E are Wisconsin drift lying on what is unquestionably Yarmouth interglacial deposits. North of the riverFig. 171at this point, figure 170, are two terraces, F and G. A section inthe drift material of the upper terrace revealed a thick depositof peaty soil, filled with shells. The material of the upperterrace is unquestionably Wisconsin in age snd was depositedin a lake which filled this valley during the retreat or advanceof the Wisconsin ice. Following the valley of Lime creek eastward, it was found that the peaty material disappears and athin covering of drift is visible. An examination of the driftshows it to be very much like Iowan drift. Light colored bowlders may be seen similar to those so common on the Iowan drift.If Iowan drift is present in the valley where the section infigure 170 is given, it is impossible to tell it. It may be that the 2Proceedings of the Iowa Academy of Science, Vol. 25 [1918], No. 1, Art. 50https://scholarworks.uni.edu/pias/vol25/iss1/50RELATION OP WISCONSIN AND IOWAN DRIFTmaterial marked I in figure 170 is Iowan. Another section alongthis same stream a quarter of a mile to the west of the sectionshown in figure 170 affords the following:SECTION ALONG LIME CREEK, FERTILE TOWNSHIP,WORTH COUNTY.1. Wisconsin drift composed of sand and gravel jn the upper portion while the lower thirty feet is a bluish gray clay filledwith bowlders and limestone pebbles 502. Black, compact, fine-grained jointed clay, containing quartzpebbles; the upper part is highly fossiliferous and containspieces of wood.Fig. 172The upper portion of horizon (2), figure 171, is undoubtedlyYarmouth interglacial deposits. It has about the same elevation with reference to the stream as horizon A in figure 170Here, as in the previous section, Wisconsin drift rests uponYarmouth deposits. A few rods to the west of the section shownm figure 171, is a very narrow, steep-sided gully. The depthat its lower end just where it enters the river is about thirtyfeet. This gully is of such recent origin that little weatheringof the drift has taken place, and since it is deep enough to cutthrough the Wisconsin drift into the underlying drift, it affordsan interesting study.3Cable: Relation of the Wisconsin Drift to the Iowan Drift as Revealed inPublished by UNI ScholarWorks, 1918542 IOWA ACADEMY OF SCIENCE VOL. XXV, 1918SECTION OF A GULLY WALL, FERTILE TOWNSHIP, WORTHCOUNTY.The west wall of the gully shows a dense, bluish black jointed clay,(1) of figures 172, beneath Wisconsin; the clay is highly jointed, theupper portion showing rather marked contortion; no bowlders arepresent, but numerous small pieces of quartz are visible. The materialmarked (2), in figure 172, is fine sand with highly distorted laminae.A section of the west bank of the north-south gully, is shownin figure 173.Fig. 173SECTION OF A GULLY WALL IN FERTILE TOWNSHIP,WORTH COUNTY.FEETA. Soil filled with roots IViB. A grayish clay, highly calcareous, showing distortion, (Wisconsin drift ) 2C. Dense bluish black, jointed clay, calcareous, the upper partshowing contortion, and containing fossil shells and piecesof petrified wood. Exposed to the base of ths gully 15D. Large sand inclusion, 8 feet wide, and extending from immediately beneath the Wisconsin drift to the bottom of the gully;sand laminated and highly distorted and having the edges ofthe lamina iron stained.1'.'. Pebbles and gravel along contact of the sand with the Kansandrift; the pebbles range in size from one-half inch to twoinches in diameter and are cemented together by iron oxide.The age of the drift here beneath the Wisconsin is Kansan.To the south of the sand pocket the joints of the Kansan driftin the upper portion, instead of being vertical, dip to the southand show some distortion which suggests strongly shearingplanes resulting from the pressure of the overriding Wisconsinice. To the north end of this same exposure, figure 173, Wiscon 4Proceedings of the Iowa Academy of Science, Vol. 25 [1918], No. 1, Art. 50https://scholarworks.uni.edu/pias/vol25/iss1/50RELATION OF WISCONSIN AND IOWAN DRIFT 543sin drift is found resting upon sand. Here the Wisconsin driftis disturbed by small synclines projecting into the sand beneathP, H, I, figure 173, and shown also in figure 174.The contact line between the sand and the Wisconsin drift iswell defined. The sand has a fresh appearance, shows littleweathering, and is probably of Wisconsin age. It seems probable that the sand pocket is not an inclusion of sand in theKansan drift, but was, previous to the advance of the Wisconsin ice, a gully cut into the Kansan drift. With the coming ofthe Wisconsin ice, the outwash from the edge of the ice filledFig. 174. View showing the folded Wisconsin drift projecting into thesand below.the gully. In the filling of the gully, the structure now seenin the sand was effected, while the distortion of the laminae hasresulted from the pressure of the overriding Wisconsin ice.Many other instances could be given, not only in Worthcounty, but in Franklin and Hardin counties as well, whereWisconsin drift is found superimposed upon what appears tobe unquestionably Kansan drift. From a careful study of thetwo drifts in the previously mentioned counties, the followingconclusions would seem warranted: (1) if Iowan drift is present beneath Wisconsin drift, it is so thin that the vigorous Wis5Cable: Relation of the Wisconsin Drift to the Iowan Drift as Revealed inPublished by UNI ScholarWorks, 1918544 IOWA ACADEMY OF SCIENCE VOL. XXV, 1918consin ice ploughed it up and mixed it so thoroughly with theWisconsin drift as to destroy all its identity; (2) the lowanice sheet may have extended no further west than the east margin of the Wisconsin drift; (3) the time interval between theretreat of the lowan ice sheet and the advance of the Wisconsinice sheet may have been of sufficient length to permit of theremoval by erosion of the lowan drift before the advance ofthe Wisconsin ice, or (4) the lowan drift dees exist beneaththe Wisconsin, but as yet has not been discovered.DEPARTMENT OP NATURAL SCIENCE,STATE TEACHERS COLLEGE.6Proceedings of the Iowa Academy of Science, Vol. 25 [1918], No. 1, Art. 50https://scholarworks.uni.edu/pias/vol25/iss1/50

Relation of the Wisconsin Drift to the Iowan Drift as Revealed in Worth County

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Relation of the Wisconsin Drift to the Iowan Drift as Revealed in Worth County

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