176 The Ohio Journal of Science [Vol. XX, No. 6, 



Sphaerium striatinum Lamark, scarce. 



Sphaerium stamineum Conrad (solidulum Prime?), a few, 



imperfect. 

 Sphaerium rhomb oideum Say, a few fragments. 

 Musculium truncatum Linsley, not scarce but almost all broken. 

 Musculium securis Prime, one valve, immature. 



Of UnionidcB, fragments only, are frequent in the top layer, 

 below the sand. None of them could be identified. 



It appears that there are several species and forms of 

 SphceriidcB in addition to those cited, and more good specimens 

 are needed for exact identification. All those listed (except 

 P. pauperculum nylanderi) are found recent in Ohio, and are 

 widely distributed. 



On the gastropods, a few additional notes may be in place. 

 LymncEa stagnalis and L. haldemani are not known to be living 

 in this section now; however, they are found in other parts of 

 Ohio, but are rare. Years ago they were listed as found, 

 e. g., in Congress Lake; but careful search there by several 

 collectors during the last twenty years has been in vain. 



The first eight species of the list, land snails — Stylommat- 

 ophora and Carychium — each represented by one or a few 

 specimens, have evidently been brought there by accident and 

 are not real parts of the fauna. Collectivel3^ they constitute only 

 a small part of one per cent of the whole number. 



It is evident that the marl was formed in a pond or lake, 

 but connected with a stream as shown by the presence of 

 SphcBrium stamineum (or solidulum) and typical forms of 

 Pisidium compressum and fallax. At least where the material 

 was collected, it was neither marshy nor directly exposed to 

 floods, or there would be numerous shells of land snails washed 

 in, and the marl would be mixed with sand and debris. It is 

 also significant that there are apparently missing some more 

 or less amphibious species, such as Segmentina, Aplexa, Pomati- 

 opsis and Sphccrium occidenfale, which preferably live in the 

 shallow water of marshy places. The first three of these are 

 represented in the Castalia marl. 



This deposit is certainly older than the one at Castalia 

 and older than some marl-like deposits, mixed with muck and 

 peat, in the southern part of Sumaiit County, e. g., in the 

 canal cut south of Summit Lake and at the southern end of 

 Long Lake. 



