90 GEORGE F. KAY AND J. NEWTON PEARCE 



The gumbo of McGee. — Dr. W J McGee applied the name 

 gumbo to the peculiar, tenacious clay which he found on his 

 Lower Till/ and in referring to the habit of weathering of this 

 till he states :^ 



Where the clay is plastic and. sand free and of the usual blue color, as in 

 the superior peripheral portion generally, it commonly weathers whitish or 

 ashen to a limited depth and forms a tenacious, intractable soil, drowning when 

 wet and baking when dry. This phase is colloquially known as "gumbo," 

 sometimes as "hardpan," and locally as "white clay," or (from its behavior 

 below the plow) "push land." 



The gumbo of Leverett. — Mr. Frank Leverett in his monograph 

 "The Illinois Glacial Lobe" described the gumbo which he found 

 associated with the IlHnoian and Kansan drifts in southeastern 

 Iowa.3 He believed that the gumbo on the IlHnoian drift was of 

 the same age as that on the Kansan drift and favored the inter- 

 pretation, although he was not satisfied fully with the view, that the 

 gumbo is the result of aqueous deposition following submergence 

 of the region. 



The gumbo and loess-silt of Bain. — Dr. H. F. Bain, in his report 

 on the geology of Decatur County, Iowa, states that blue to drab- 

 colored gumbo which in places overHes the Kansan drift and is 

 distinct from the drift belongs stratigraphically with the loess, and 

 presents the view that the gumbo suggests a quiet-water deposit 

 which has been compacted or puddled by water.'* In earlier 

 geological reports of counties in Iowa the same author refers to 

 similar material. In his report on Keokuk County, Iowa, he 

 refers to a stiff, yellow to blue-gray, plastic, non-calcareous clay 

 which is on the Kansan drift and beneath the loess on the uplands, 

 and states :5 "It seems to be a deposit closely akin to the loess and 



' Kansan drift of present classification. 



^ W J McGee, "The Pleistocene History of Northeastern Iowa," U.S. Geol. Surv., 

 Eleventh Ann. Rept., Part I (1891), p. 509. 



3 Frank Leverett, "The Illinois Glacial Lobe," U.S. Geol. Sun., Monograph 

 XXXVIII (1899), pp. 28-33. 



4 H. F. Bain, " Geology of Decatur County, Iowa," Iowa Geol. Surv., Vol. VIII 

 (1897), p. 292. 



5 H. F. Bain, " Geology of Keokuk County, Iowa," Iowa Geol. Surv., Vol. IV (1894), 

 p. 302. 



