388 



JOHN L. TILTON 



Dakota sandstone, apparently preclude the possibility of success- 

 ful mines even if coal were located. 



The presence of this fault and of others in a parallel direction 

 with upKft to the north has also an important bearing with reference 

 to the distribution of coal toward the north and northeast that is 

 very noticeable in northern Adair and southern Guthrie and Dallas 

 counties/ and, combined with erosion, explains the westward trend 

 of exposures of the Des Moines stage in this region. It also intro- 

 duces a new factor to combine with unconformity at the base of the 

 Des Moines stage to explain why coal is found in certain localities 

 (as near Panora and Boone) and not in others. 



legend 

 S, Stvery shale. 

 N, Mda'juav coal 



0, Sate o/Onadh 

 X, 3<M i/Iatait h. 

 L,Ba<t<>/lonsir,s 



HMfittfTloiyi 



The Virata a/- 

 /tcttd ty/ault/ng 



T/ie tt rata a//ecfdiyioCil^t. 

 /au/iino'arxTt/ie hatt 'tut ling: 

 /yite ihe c//i^t[et/>ee:ttlly7nO). 



Fig. 4 



Oil. — The presence of a dip fault extending through south- 

 western Iowa toward the oil fields farther southwest, with strata 

 in Iowa monoclinal, dipping southwest, and crossed by low anti- 

 clines,^ present a series of facts that cannot be overlooked with 

 reference to oil, even though no traces of oil have been found. 

 Across the river in Nebraska a little fault exists in Jones Point 



' In view of the presence of this parallel fault Bain's report on Guthrie County 

 makes very interesting reading {Iowa Geol. Surv., Vol. VII). On pp. 428-29 he 

 describes the upper division of the Des Moines stage as duplicating the lower division, 

 and on p. 455 states that beds, found "probably represent the upper portion of the 

 Cherokee shales." Leonard (VIII, 91) speaks of an anticline in the southwestern 

 part of Dallas County, the county next east of Guthrie County. 



^George L. Smith, "Carboniferous Section of Southwestern Iowa," loiva Geol. 

 Surv., XIX, 624. 



