THE ILLINOIAN ICE INVASION 287 



Number 2, referable to the Sangamon or Illinoian loess, contained six 

 species of mollusks. 



Pyramidula perspectives Succinea obliqua 



" cronkhilei anthonyi Helicina occulta 



Pupilla muscorum Galba obrussa ( = desidiosa) 



Leverett 5 also lists a number of species from this locality, these being: 

 Succinea obliqua Oreohelix iowensis 



" lineata ( = grosvenorii) Pyramidula cronkhilei anthonyi 



Helicina occulta " perspectiva 



In Louisa County, at Grandview, from the bottom of a well 12 feet deep, 

 four species of mollusks were collected. 6 



Succinea avara Galba cape rata 



" grosvenorii " humilis modicella 



In the same county, Udden 7 states that the Sangamon old soil is especially 

 pronounced in the east bluffs along the Iowa River, northeast of Wapello. In 

 the bluff of the Mississippi River, where the Muscatine North and South R. R. 

 has made a cut, the Sangamon soil or peat is partly replaced by gymnospermous 

 wood. In Sweetland Township, Muscatine County, (SW34 Sect. 12, T. 77 N, 

 R. 1 W) elephant bones were observed in a peat deposit containing gym- 

 nospermous wood. 8 The elytra of beetles have also been found, and at two 

 other points the remains of the elephant have been observed. The succession 

 of strata noted below is exhibited in this region: 



Loess 



Sangamon soil 



Illinoian till 



Buchanan gravel and Yarmouth soil 



Kansan till 



Aftonian 



Nebraskan till 



From the Sangamon soil in the bed of Otter Creek, near Morning Sun, 

 (NWJ4 Sect. 25, T. 73 N, R. 4 W) several bones of a mastodon were ob- 

 tained. 9 An elephant tooth was also found in a well near a tributary of Indian 

 Creek, which may have come from the same horizon. 8 The antler of a deer 

 (probably extinct) was reported by Udden from NW}^ Sect. 14, T. 74 N, R. 

 3 W. 



5 Illinois Glacial Lobe, p. 169. 

 'Udden, Geol. Iowa, XI, p. 112. 

 7 Geol. Iowa, XI, pp. 101-111. 

 *Op.cU.,p. 110. 

 ' Udden, Iowa Geol. Surv., IX, p. 350. 



