292 



Dr. John T. Plummer on the 



of some species of Gorgonia. To the naked eye they have the 

 appearance of ordinary fucoides ; but under a glass of considera- 

 ble magnifying power, the structure mentioned is very obvious. 



Fig. 7 



I know that in perhaps most instances no organized structure is 

 visible ; but it is possible for that to be obliterated, while the 

 general form is preserved, and I have therefore made the above 

 statement to excite others to further microscopic examinations of 

 these fossils. 



Of the Radiaria, we have, so far as I have seen, but a few 

 examples ; here and there fragments of small encrinites are found, 

 and still more rarely, equally small pentacrinal joints. 



Among the zoophytes, I find two species of Cyathophylla, of 

 which the C. ceratites is much the most common ; Favosites 

 Clifordi, of which I have discovered but a single specimen ; fre- 

 quently specimens of Eschara, and a few species of Astrea, of 

 Calamopora, and of Cosinopora. Most of these fossils are ex- 

 ceedingly common, and when broken in the rock, easily arrest 

 the attention by their white interior. A step-stone at my door, 

 with a surface of six square feet, exposes sections of eighty one 

 Cyathophyllse. The poras mentioned, are strewed every where 

 along our river banks. The Eschara is perhaps confined to the 

 "marlite." 



Bivalves. — Of these, we have two species of Delthyris ; the 

 IStrophomena alternate/,, S. semiovalis, S. deltoidea, and I think 

 three other species ; the Orthis testudinaria, and two other spe- 

 cies ; a small Pentamera ; the Atrypa Wilsoni, and one other 

 species ; several species of Pterinea ; two species of Avicula ; a 

 very rare species, which, as far as the shell is exposed, has the 



