THE ILLINOIAN ICE INVASION 303 



drift along the river shore of the Ohio and the Miami. Later these were 

 traced to their source in the geological deposit. 



Vallonia pulchella. Traces only. 



Polygyra tridentata. More elevated and more deeply striated than recent form. 



" tridentata, var. Mouth much depressed; deeply striated. 



" in fleet a 



" profunda 



" albolabris. Scarce 



" exoleta ( = zaleta) 



" multilineata. Not found alive within 20 miles of Lawrenceburg. 

 palliata 



" appressa 



" elevata 



" pennsyhanica. Rare alive in vicinity. 



" thy raid es 



" mitchelliana. Rare alive. 



" stenotrema 



" monodon. Very rare. 

 Pupoides marginatus 

 Bifidaria contracla 



" arm if era 

 Cochlicopa lubrica 

 Circinaria concava 

 Vitrea hamntonis 

 Gastrodonta ligera 

 Pyramidula alternata 

 " solitaria 



" cronkhitei anthonyi( = s!riatel!a). Rare. 

 " perspectiva. Rare. 

 Helicodiscus parallelus. Rare. 



Succinea species. Nothing as large found in the vicinity. 

 Pamatiopsis lapidaria. Never found alive near Lawrenceburg. 



Forest beds are also found at Hickman's Landing, Switzerland County, 

 two miles above Florence. This bed of blue clay, which contains leaves and 

 wood and is 4^ feet thick, may be traced in the river bank without interrup- 

 tion for 20 rods. Ochreous deposits occur above and below this deposit, as at 

 Lawrenceburg. 97 Leverett 98 believes that the old soil at Lawrenceburg is of 

 Sangamon age and overlies Illinoian drift, the upper deposits, often aggregat- 

 ing 85 feet in thickness, being referable to Wisconsin age. 



In Gibson County Sangamon soil is frequently noted beneath loess de- 

 posits and above Illinoian till. A section, situated four miles west of Wades- 

 ville," indicates the position of this soil. 



" Warder, Geol. Surv. Ind., 3-4 An. Rep., p. 408. 



'• Mon. XLI, p. 267. 



" Fuller and Clapp, Patoka Folio, p. 4. 



