SCIENCE 



[N. S. Vol. XLIV. No. 1124 



epilinmion, thermocline and hypolimnion was pro- 

 nounced, even after strong winds. Evaporation 

 amounted to about two tenths inch per twenty-four 

 hours. Eainfall caused an immediate rise in the 

 hydrograph. 



The Hollusca of the Loess of Crowley's Eidge, Ar- 

 kansas: B. Shimek. 

 A discussion of the fauna of the loess of this 



ridge, with a list of species. 



Superimposition of Kansan Drift on Sub-Aftonian 



Drift in Eastern Iowa: Morris M. Leighton. 



During the reconstruction of the C. M. & St. P. 

 By., new cuts were recently opened up in eastern 

 Iowa, in the vicinity of Delmar Junction, showing 

 a body of sub-Aftonian drift beneath Kansan 

 drift. A soil zone, together with a mineralized 

 stump and fragments of wood, separate the two 

 drifts. The Aftonian interval is recorded also by 

 several feet of leaching of the lower till which is 

 in contrast to the calcareous portions of the over- 

 lying till. 



These exposures are of unusual importance to the 

 Pleistocene geology of Iowa in that they show that 

 the sub-Aftonian ice-sheet as well as the Kansan 

 invaded eastern Iowa, and they throw light upon 

 the data of the superimposition of certain major 

 streams in eastern Iowa. 

 Pleistocene Exposures on Capitol Hill: James H. 



Lees. 



The area made classic in Pleistocene geology by 

 the studies of McGee and Call is now exposing to 

 even better advantage the relations of Wisconsin 

 drift, pre-Wisconsin loess and Coal Measures. No 

 pre-Wisconsin drift is present. Fifteen feet of 

 loess, buff except as weathered to gray, is overlain 

 by Wisconsin till, with a zone of mingled loess and 

 fossil-bearing drift between. A great lens of sand 

 lies within the loess. The possible relations of the 

 strata are discussed. 



Progress Seport of Geological Work in the Driftless 



Area: A. C. Trowbridge. 

 The History of Devil's Lake, Wisconsin: A. C. 



Trowbridge. 

 An Outlier of the Clinton Formation in Dubuque 



County : J. V. Howell. 



Describes an occurrence of an oolitic, ferrugi- 

 nous layer at the Maquoketa-Niagaran contact 

 seven miles west of Dubuque, Iowa. The material 

 apparently is identical in lithologic character and 

 stratigraphic position with the "Clinton" ore of 

 eastern Wisconsin, which Savage and Boss have 

 recently shown to be of Ordovician age. 



Geological Conditions Regarding Oil and Gas in 



Southeastern Iowa: George P. Kay. 

 The Super-Kansan Gumbo of Southern Iowa: 



George P. Kay. 

 Progress Report on Studies of the lowan Drift by 

 the Iowa Geological Survey and the United States 

 Geological Survey: George P. Kay. 

 Bibliography of the Loess: E. J. Cable. 

 A Correlation of Peneplains in the Driftless Area: 

 Urban B. Hughes, presented by A. C. Trow- 

 bridge. 

 Major Discissive Lines in Prairie States: Charles 

 Keyes. 



Decipherment of the geotectonic features of the 

 Prairie region of the Continental Interior is at- 

 tended by so many difficulties that little real ad- 

 vance is recorded in a half century. Lately, how- 

 ever, new data on the problems involved became 

 available. Considering alone fault-lines of rela- 

 tively large displacement the Iowa field affords 

 some unusually instructive information. The great 

 Cap-au-Gres fault is found to extend into Iowa, 

 where its greatest throw is not less than 100 feet. 

 The remarkable Port Dodge fault with a throw of 

 about 125 feet has economic bearings of high im- 

 portance. The Bed Oak fault has a displacement 

 of more than 350 feet. The famous La Salle fault 

 seems to find expression near Dubuque and else- 

 where in the northeastern part of the state. In 

 western Iowa the fault-spacing appears to be quite 

 regular with an approximate value of 25 miles. 

 Becognition of this fact suggests the probable exist- 

 ance of other notable faults of the series and fully 

 explains many hitherto apparently incongruous rec- 

 ords regarding the areal distribution of the various 

 terranes of the region. 



Wide Areal Extent of Chouteau Limestone: 



Charles Keyes. 



Long prevailing misconceptions concerning the 

 stratigraphic extent and relations of the Chouteau 

 limestone, originally described by G. C. Swallow in 

 central Missouri, and a manifest tendency of late 

 years to disregard the terrane as a useful and 

 valid mapping unit have recently led to a reexami- 

 nation of the section at the type locality and a 

 careful correlation of the formation as there ex- 

 posed with other sections east and north. In the- 

 latter direction it now appears that the Chouteau 

 limestone retains its characteristic features and 

 relationships to the Minnesota boundary, where> 

 with other Paleozoic terranes, it rises against the- 

 old Siouan arch — a Triassic mountain axis of large 

 proportions. Towards the east, by complete thin- 



