950 



SCIENCE 



[N. S. Vol. XLI. No. 1069 



Studies on Barium Sulfate: P. L. Bluementhal 



AND S. C. GURNSEY. 



A Comparison of Some KjeldaM Methods for Ni- 

 trogen Determination.- P. L. Bluementhal 



AND G. P. PLAISANCE. 



The Ste. Genevieve Formation and Its Strati- 

 graphic Relations in Southeastern Iowa: Stuakt 

 Wellee and Francis M. Van Tuyl. 

 Eeeent field studies have shown that the Pella 

 limestone, which was formerly regarded as the 

 uppermost subdivision of the St. Louis, is forma- 

 tionally distinct, being separated from the true St. 

 Louis beneath by an unconformity and a remark- 

 able basal sandstone. The previous reference of 

 this member to the Ste. Genevieve upon the basis 

 of its fauna is, therefore, borne out by the field 

 evidence. 



The Occurrence and Origin of the Iron Ores of 



Iron HiU, Near Waulcon, Iowa: Jesse V. 



Howell. Introduced by G. P. Kay. 

 The Extension of the Wisconsin Drift Southwest 



from Des Moines : John L. Tilton. 



This newly recognized area of Wisconsin drift 

 extends from Valley Junction just west of Des 

 Moines for five miles to the south. In all direc- 

 tions, east, south and west, from this strip, now 

 only about a mile wide, the topography is that of 

 a typical area of Kansan drift. 



The Age of the Terrace South of Des Moines, 



Iowa: John L. Tilton. 



A low terrace is very noticeable near Des Moines 

 and along streams flowing into the Des Moines from 

 Warren County. The topographic maps give evi- 

 dence of a similarly related terrace further south- 

 east and then north along the Mississippi River to 

 within the area of Wisconsin drift in that part of 

 the state. The terrace is composed of sand and 

 gravel forming a continuous deposit to a depth of 

 thirty feet, post-Wisconsin in relation, and with 

 Wisconsin or post-Wisconsin fossils: Bison, Eangi- 

 fer, Symbos. 



The First Coal-washing Plant in Iowa; The Min- 

 eral Industry in Iowa During the Past Decade: 

 George F. Kay. 

 The Occurrence of Barite in the Lead and Zinc 

 Districts of Iowa, Illinois and Wisconsin: W. D. 

 Shipton. 

 Precise Criteria of Terranal Correlation : Charles 

 Keybs. 



The signal failure of our state and federal geo- 

 logical surveys to give us working classifications 

 of local geologic formations that are readily ad- 



justable to the general continental scheme has re- 

 cently led to the adoption by the various bureaus of 

 somewhat arbitrary methods in order to make pub- 

 lished records immediately available. In casting 

 about for a suitable area for which to construct a 

 generalized section of local rocks the quadrangle, 

 as ordinarily selected, appears to be much too small 

 to be of any real service. The county is likewise 

 too limited in extent. In size the state seems to be 

 most satisfactory for trial tests in continental 

 problems of exact correlation. A number of these 

 generalized state sections reduced to identical taxo- 

 nomic schemes are compared. 



Mountain Structures in Plains: Charles Keyes. 



The larger tectonic features of the substruc- 

 ture of the prairie region of the continental in- 

 terior are of unusual interest because of the fact 

 that well-defined mountain structures are now dis- 

 covered here for the first time. A carefully con- 

 structed geologic cross-section extending from the 

 northwest corner of Iowa to the southeast corner 

 of Missouri presents one of the most perfect syn- 

 elinoria known. Within this remarkable basin are 

 preserved our great coal deposits. 



At the north end of this synelinorium is the 

 structural remnant of old Triassic mountains, a 

 range which in its prime was comparable to the 

 Appalachians of to-day. At the south end is the 

 Ozark dome of Tertiary date. Associated with 

 the great trough is a noteworthy system of pro- 

 found dislocations. 

 Exhumed Sea-coasts: Charles KIeyes. 



A curious geologic coincidence occurs on the 

 shores of Puget Sound. There has been in this 

 region during late geological times more or less 

 oscillation of the land. In a previous cycle the 

 hard igneous rocks were carved out by the waves 

 into low, irregular sea-cliffs. On the sinking of 

 the islands sands and gravels covered this belt to 

 considerable depths. To-day, with a marked up- 

 rising, the new shore-line is contraposed on the 

 ancient one. In a quite remarkable way the latter 

 is being now exhumed by the action of the waves. 

 Progress Meport of Physiographic Work in the 



Driftless Area: A. C. Trow^bridge. 

 The Paleontology and Stratigraphy of the Upper 



Carboniferous of Iowa: George L. Smith. 



The Loess of Peceel, Bungary (with lantern 



slides) : B. Shimek. 



A discussion of true loess and an underlying 

 water deposit which has been classed as loess. The 

 true loess contains a strictly terrestrial molluscan 



