The Proceedings of the Iowa Academy of Science Volume 6

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1899 Excerpt: ... Drift, yellowish above, 'bluish below (Wisconsin) 20 Loess, sandy below 20 Clay, blue with much coarse gravel exposed The loess is silicious throughout and the upper four feet is distinctly joined and stained a faint yellow-brown along the joint planes. It grades downward into a massive, structureless, pale blue clayey silt which contains, in places, an abundance of root casts, wood fragments and black, Carbonaceous spots and emits a distinct swamp like odor. The entire deposit is highly calcareous and carries a rich gastropod fauna. Prof. B. Shimek identified the following forms, the majority of which are strictly terrestrial. Zonitoides shimekii, (Pilsbry) P. & J. Sphyradium edentulum alticola, (Ingersoll) P. &. J. Pupa muscoruid, L. Bifidaria pentodon, (Say) Sterbi. Vertigo ovata, Say. Corulus fulvus, (Mull). Polygyra multilineata, (Say) P. & J. Pyramidula striatella, (Anth.) P. &. J. Vallonia costata, (Mull) Sterbi. Succinea lineata, Binn. Succineaavara, Say. Limncea humllis, Say? Loess concretions are relatively scarce and are diminutive in size. The deposit shows no signs of oxidation or leaching where the drift covering is thick; but where the covering is so far reduced as to afford imperfect protection from the weathering agents, both leaching and oxidation may be noted, and here, alone, are lime concretions to be found. It is obvious that little or no alteration took place prior to the deposition of the overlying drift. The outcrop along Onion creek is an almost exact duplicate of the Walnut creek section. The drift mantle is thinner, and from two to five feet of loess has been stained to a yellowish buff, and loess concretions are more in evidence, thus attesting to the greater progress made in leaching. Here, again, the upper port...