No. 20.] 6» 



I have also added a cast of the skull and one lower jaw of tlie 

 Castoroides ohioensis. The original was found near Clyde in Wayne 

 county, N. Y. 



In addition to the above, I have added to the collection in palae- 

 ontology, from the Trenton limestone : 



One new species of PALiEOPHYCUS. 



An undescribed marine plant belonging to a new genus. 



Two specimens of Tellinomya nasuta. 



Several perfect specimens of Tellinomya duhicu 



" perfect specimens of Modiolopsis mytiloides. 



" good specimens of PleMrotomaria lenticul&iis. 



" " " of Biicania punctifrons. 



'* ** " of Bucania tricarinatcu 



" " " of Cyrtolites compressus. 



Good specimens of Holopea obliqua. 

 A new species of the genus Subulites. 

 One or two new species of Endoceras. 



in all, fifty specimens have been added to those previously in the 

 cases from the Trenton limestone. Besides these, several hundred 

 specimens of different species 'have been obtained (from the same 

 rock) ; but as they are not better than those previously n the 

 •collection, I have not placed them in the cases, and they remain 

 packed iu boxes for future disposition. 



From the Clinton group some very interesting specimens have 

 been obtained, showing the existence of sea beaches with the tracks 

 or trails of marine animals upon the sand. At least one hundred 

 specimens, containing fossils, have been added from this group. 

 Among these are perfect specimens of the Pentamerus oblongus ; 

 several species of Atrypa, and others which are undescribed. I 

 may add, that the number of species of fossils in this group has 

 been more than doubled by the collections made during the past 

 season. 



From the Niagara group, there have been added a considerable 

 number of corals : at least twenty undescribed species have been 

 added during the past summer. About twenty specimens of Caryo- 



