POSTGLACIAL BIOTA OF THE GREAT LAKES REGION 145 



Pseudosuccinea columella, scarce. Valvata sincera(?). 



Galba humilis modicella, rather frequent. Sphaerium sulcatum, rather frequent. 



Galba humilis rustical), rather scarce. Sphaerium striatinum, form. 



Galba obrussa decampi, common. Sphaerium solidulum, scarce. 



Planorbis campanidatus, not common. Sphaerium rhomboideum, very scarce. 



Planorbis binneyi, very scarce. Muscidium truncatum, rather frequent. 



Planorbis antrosus, common. Muscidium secure, scarce. 



Planorbis exacuous, frequent. Muscidium rosaceum, scarce. 



Planorbis rubellus, rather scarce Pisidium compression, common. 



Planorbis crista cristatus, scarce. Pisidium fallax, scarce. 



Planorbis parvus, common, rather variable. Pisidium variabile, frequent. 



Planorbis alb us ( = hirsutus), common. Pisidium adamsi affine, rather scarce, juve- 



Ancylus parallclus. nile to adult represented. 



Ancylus kirtlandi. Pisidium abditum, rather scarce. 



Gundlachia species, first stage, one specimen Pisidium pauperculum, abundant. 



Physa gyrina, rather scarce. Pisidium walkeri, scarce. 



Physa Integra, scarce. Pisidium scutellatum, scarce. 



Physa heterostropha (?), scarce. Pisidium ohioense, scarce. 



Physa sayii, large, rather frequent. Pisidium splendidulum, frequent. 



Amnicola limosa, common. Pisidium rotundatum, scarce. 



Amnicola lustrica, common. Pisidium medianum, frequent. 



Amnicola emarginata, scarce. Fragments of Unionidae only in a thin top 



Valvata tricarinata, common. layer which mav be of later origin. 



2. Vertebrate Life 



Hay 71 refers the deposit in Holmes County containing the Megalonyx 

 skeleton to post- Wisconsin time, with the following note: "The terminal 

 moraine of the Wisconsin drift sheet runs through the county in an east by 

 northeast direction, and this had led to the formation of a small lake north of 

 it, which finally became a swamp filled up with peat. By some means the 

 Megalonyx had left his remains in the lake after the formation of the shell marl 

 and before the growth of the peat. It is evident that this sloth existed after 

 the retirement of the Wisconsin drift-sheet and long enough after it for the 

 climate to become sufficiently warm to permit this animal to wander into \^ 

 Ohio." Dr. Hay also cites Megalonyx from Norwalk, Huron County, estab- 

 Ushing beyond doubt the occurrence of this giant sloth after the retreat of the 

 Wisconsin ice sheet. 72 



Mastodon remains have been reported from various parts of Ohio. Those 

 referable to post- Wisconsin time are listed below. 



Bucyrus, Crawford County, in swamp, embedded in muck and marl. 73 

 Clay Township, 2% miles east of St. Johns, Auglaize County, in swamp, under 

 3 feet of black muck and 5 feet of marly clay; 74 Springfield, Lucas County, in 



71 36th An. Rep., Dept. Geol. Nat. Res. Ind., p. 558. See foot-note 70. 



72 Science, XXXIX, p. &¥>, 1914. 



73 Winchell, Geol. Ohio, II, p. 247. 



* ♦ 



