350 



LIFE OF THE PLEISTOCENE 



5. Sand with freshwater shells feet 6 i aches Peorian. 



6. Sand and gravel 6 " " Iowan. 



7. Sand with fresh water shells " 8 " Yarmout 



8. Soil and subsoil „ 6 " " 



Height of section 38 feet 2 inches 



From number 5 a number of mollusks were obtained, the species being 

 noted below: 19 



Planorbis parvus 



" bicarinalus (—antrosus) 

 P scudosuccinea columella 

 Physa heterostropha? 



Campeloma decisum 

 Goniobasis virginica™ 

 Unio siliquoides (=luleola) 

 Sphaerium ( = Cyclas) 



A section at Stillwater, Washington County, may possibly contain a stra- 

 tum referable to the Peorian interval. 



Section" of Strata at Stillwater. 



1. Disturbed sand with some boulders 5 feet 



2. Fine sand with nearly horizontal strata 2-6 



3. Gravel and boulders v 0-4 



4. Very fine sand, horizontal stratification 15 



5. Coarse gravel and boulders 4-6 



6. Horizontal strata of fine sand 30-40 



7. Tripoli bed lies next below this fine sand 



Near the bottom of number 6 the tusk of a mastodon was found. 



There are several records which indicate the presence of the remains o 

 life beneath the Wisconsin drift and above the Iowan drift, and hence referabl 

 to the Peorian interval. In Carver County 21 a well section shows the succe: 

 sion of strata to be as indicated below: 



Till, with many boulders 2-6 feet 



Clay, with Unios, 5 feet below surface „ 20-40 feet 



Sand x feet 



The Wisconsin till appears very thin, but can be nothing else. 



In Chisago County, 22 at Nessel, a well section exposes the strata noted be- 



low: 

 Soil.. 



feet 



Yellow till : 8 



Soft blue clay with peaty portions and decaying fragments of wood 4 



Sand 1+ 



Height of section 15 



19 Owen, Rep. Geol. Surv. Wis., Iowa, and Minn., p. 489. Goniobasis virginica is an 

 erroneous identification and Physa heterostropha is doubtful. 

 25 Winchell, Geol. Surv. Minn., Final Rep., II, pp. 397-398. 



21 Op. cit., p. 133. 



22 Op. cit., p. 418. 



