the drift material over the surface, and the 



.able nature of tin' rock. Prom what lias been said, it 



rronp touches Lake Michigan, and that the 



I Hamilton Groups (if both exist) must pass entirely 



.•.h the lake, re-appearing probably in Mason, Oceana and 



while the Marshal] Group proceeds in tin; 



direction of Newaygo ami Lake connti 



OH and f the various ontc 



appropriately given at the present time. 

 an enumeration of all the ontci 



tj of the Marshall Group nsid- 



«?rable in: :h in consequence of the number of indi- 



viduals and species found fossil, and the distinctness of the 

 fauna from that of other regions in the same geological horizon. 

 . le attention has been bestowed Qpon the collections 

 up, but not a single satisfactory identification 

 has yi made. The most abundant and characteristic 



fossils at the various localities belong to the genera Nw-ula, 

 (5 sp. . s _ ipecios,) Belleroph&n, (3 species,) Ortho- 



■•>), Jlyaltna and Clymcnia (5 species). Besides 

 I have referred to Oyriocerat, 4 species, Cryptoceras, 

 2 spacies, Trocholik -cms, Goniatilex, 5 species, 1'huroto- 



maria. 1 - TeUina, 1 I Cardium, 9 species, Luema, 



I, Orthti and other Brachiopods, one or more 

 species each. 



ver, numerous - which hare nsi 



particnlarly examined, am >ng which are a few fish remains 



and land plants. A- 1 inten ! commonicating to the public at 



further particular regarding this assembl i 



. I refrain from extended remarks at the present time. 



I rer, in printing this report, ena- 



I a few observations relative to the Clymenia). 



_■ to all ti,o two I menia and 



vridely distinguished by the position of the 



siphon, being interior in the former and exterior in the latter. 



;rue that all my specimens of Cephalopoda from the Mai 



