388 A. M. Edwards — Deposit of Diatomacece. 



Pleurosigma angularis, W. S., Balticum, C. G. E., delicatulum, 

 W. S., oximium, F., elongatum, W. S., fasciola, F. T. K., hippo- 

 campus, C. G., obscurum, W. S. 



Podosira monilformis, C. G. E., Montagnei, F. T. K. 



Ptxilla ? Baltica, A. G. 



Rhabdonema Adriaticum, L., arcuatuaum, F. T. K. 



Synedra affinis, F. T. K, lunaris, C. G. E., pulchella, F. T. K., 

 ealina, W. S., tabuiata, F. T. K., ulna, F. T. K. 



Stictodiscus craticula. 



Stephanodiscus corona, C. G. E., Niagara, C. G. E. 



Stauroneis acuta, W. S., anceps, C. G. E., aspera, W. S., 

 saliua, W. S., legumen, C. G. E., maculata, J. W. B., phoenicen- 

 teron, C. G. E., pteroidea, C. G. E., gracilis, C. G. E., fenestra, 

 C. G. E. 



Surirella acuta, C. G. E., Brightwellii, W. S., crumena, 

 A. de B., cardinalis, F. K., Davidsonii, A. S., Fastuosa, C. G. E., 

 gemma, C. G. S., gracilis, A. G., linearis, W. S., Molleriana, A. S., 

 ovalis, A. de B., Ratrayii, A. S., recedens, A. S., robusta, C. G. E., 

 spleudida, C. G. E., salina, W. S., Suevica, Z. 



Schizonema cruciger, W. S., divergens, W. S., hyalina, W. S., 

 Smithii, C. A. A. 



Tetragramma Americana, T. W. B. 



Tabeixaria fenestrata, F. T. K., flocculosa, F. T. K. 



Triceratium alternans, T. W. B., favus, C. G. E., reticulum, 

 C. G. E. 



Van Heurkia rhomboides, A. de B. 



We now come to the geology of the Newark Champlain (?) 

 deposit. I understand the Champlain deposit to be formed 

 when the melting of the glacier which succeeded the Tertiary 

 age. The first were glaciers forming the glacial period and 

 then they melted and formed the Champlain period. When 

 the glaciers were nearly melted, the Diatomacese lived in the 

 fresh water, and their shells were deposited when the stream 

 of the Champlain period rushed down from the North. The 

 deposit was mostly clay and covered the states where it is now 

 found. From New Brunswick to Pennsylvania on the Atlan- 

 tic coast of North America it is formed covering the whole 

 country. The clay was of course fresh water, and the Diato- 

 macese were also fresh water. By and by salt water flowed in 

 and formed brackish pools on the coast. As this was raised a 

 brackish clay was formed, and this I call the raised or sunken 

 beach. Dr. J. S. Newberry calls it the Littoral Plain. He 

 describes it in the geological history of New York Island and 

 harbor in the Popular Science Monthly, vol. xiii. The 

 fresh-water deposits are innumerable, but really are one and 

 form the clay at the bottom. Upon this is the raised coast. 

 The raised coast forms two deposits in the Newark meadows. 

 Upon this is a clay of fresh water Diatomacese, and lastly 

 comes the recent clay now forming. 



