August 15, 1913] 



SCIENCE 



241 



lowan Cretacic Sequence: Charles Keyes. 



Deposits homotaxially equivalent to the Cretaeie, 

 or Chalk, formation of England were first recog- 

 nized on the American continent along the Big 

 Sioux Eiver in a district which is now incor- 

 porated in the state of Iowa. This correlation 

 was almost the first attempt to apply the fossil 

 criteria to the rocks of this country. Less than a 

 decade had elapsed since this means had been 

 formulated by William Smith in England. The 

 use of the method was introduced in 1809 by 

 Thomas Nuttall, an English botanist who during 

 the following year ascended the Missouri Biver 

 from St. Louis. Notwithstanding the fact that 

 this region was visited repeatedly during a whole 

 century which has elapsed since Nuttall 's visit, it 

 has been only within the last year that the com- 

 plete Cretacic section in Iowa has been with cer- 

 tainty determined. The total thickness of the 

 beds is now known to be not less than 800 feet. 

 It is separable into seven distinct terranes. These 

 are defined as the Nishnabotna sandstones, the 

 Sergeant shales, the Ponca sandstone, the Wood- 

 bury shales, the Crill limestone, the Hawarden 

 shales and the Niobrara limestones. 



Terranal Bifferentiation of Devonic Succession in 



Iowa: Chaeles Keyes. 



Upon faunal grounds, as well as for lithological 

 and stratigraphical reasons, the main Devonie 

 limestones of Iowa, or the Cedar Valley formation 

 as they are most widely known, were found more 

 than a score of years ago to be separable into 

 five well-defined terranes. No special geographic 

 names were attached to these several subdivisions. 

 They are, however, commonly recognized as valid 

 by all who have studied the field in detail during 

 the term of years mentioned. Calvin published 

 the general section with these division-lines indi- 

 cated but he gave no distinctive local designations. 

 The terranes are easily distinguishable over wide 

 areas. For the lower number the title Fayette 

 formation is retained. The others are called the 

 Solon, Eapid, Coralville and Lucas formations. 

 The subdivisions are briefly characterized. 



Possible Occurrence of Tertiary Deposits East of 

 the Missouri Biver: Chables Keyes. 

 Deposits of Tertiary age have never been recog- 

 nized as occurring within the limits of Iowa. 

 Their presence, however, has long been surmised. 

 The repeated invasions of glaciers have naturally 

 removed nearly all vestiges of any soft rocks 

 which may have existed in pre-glacial times upon 

 the older indurated strata. 



The majority of such remnantal deposits are 

 easily mistaken for phenomena connected with the 

 glacial drift-sheets. Yet there are several of these 

 sections along the Big Sioux Eiver, for instance, 

 the beds of which appear not to be of glacial 

 origin. They seem to belong to isolated patches 

 of the Tertiaries which are fully represented in 

 the eastern parts of South Dakota and Nebraska. 

 One pocket in particular, exposed near Sioux City, 

 and called the Eiverside sands, now appears to be 

 unquestionably Tertiary in age. 



Wright's "Ice Age" on the Genesis of Loess: 



B. Shimek. 



In the second edition of Wright's "Ice Age" 

 objections are made to the ffiolian hypothesis of 

 loess origin. This paper aims to meet these ob- 

 jections, and sustains the ffiolian hypothesis. 



Preliminary Note on the So-called Loess of South- 



western loiva: James Ellis Gow. 



This is a discussion of the nature and origin of 

 a clay found in Adair County at the surface of 

 the drift. It contains no gravel or bowlders and 

 in near-by localities has been described as 

 "loess." Investigation shows that it is neither 

 aqueous nor solian in origin and that it may occur 

 in the Kansan drift at any and all depths. 



The Proper Use of the Geological Name, Bethany: 



John L. Tilton. 



The term Bethany Palls limestone, or Bethany 

 limestone, has been used with three different mean- 

 ings. It properly applies to the second limestone 

 of the section foimd at Winterset, which limestone 

 is called the Earlham. 



A Pleistocene Section from Des Moines South to 



AUerton: John L. Tilton. 



Along the new railroad line from Des Moines to 

 Allerton are fine exposures of the Pleistocene, 

 photographs and descriptions of which should be 

 preserved for reference since the relation of the 

 deposits will very quickly become obscured. The 

 exposures present strong evidence, supported else- 

 where, that the so-called "gumbo" was deposited 

 in the closing stages of the Kansan, and that it is 

 but one form of a deposit for which collectively 

 the term Dallas deposits is here suggested. Kan- 

 san drift and Des Moines shales are well exposed, 

 but no Aftonian nor Nebraskan. Loess is found 

 only in the northern portion of the area. 



Mound and Mound Explorations in AUamalcee 

 County, Iowa: Ellison Orr. 

 The paper covers in a general way the pre- 



