274 REVIEWS — GEOLOGICAL SURVEY OF CANADA. 



{Magaritana) margaritiferus [with several other species (as Z7. {M.) 

 marffinata, and U. (M.) rugosa, found by Mr. Billings at Lake Clear), 

 but U. arcuatus and U. margaritiferus are perhaps identical]. Anodon 

 fluviatilis, found by Mr. Billings at Lake Clear. 



Arcade: — {^Leda {Yoldia) Umatula, Prof. Dawson] . The dredge 

 will undoubtedly reveal the esistence of other species in the St. 

 Lawrence Grulf. 



MxTiLiDiE : — Mytilus eduUs. [Modiola modiolus, M. deeussata^ 

 Prof. Dawson]. 



OsTBMiDM :^— Anemia ephippium. Pecten Islandicus ; P. Magel- 

 lanicus. 



Palliobranchiata or Brachiopoda. 



B,HTNCONEiiiiiDiE : — \_Bhynconella psittacea — not obtained by Mr. 

 Bell, but known to occur in the Gulf of the St. Lawrence]. 



The valuable report communicated by Professor Hall, contains 

 descriptions of various new species of Canadian graptolites, obtained 

 within the last few years, in a condition of extraordinary preservation, 

 in the Hudson Biver group of Point Levi, opposite Quebec. As this 

 report will form the subject matter of one of the forthcoming Decades 

 of Canadian Organic Eemains, its contents will be brought before the 

 notice of our readers in another number of the Journal. At present, 

 therefore, we will merely observe, that Professor Hall considers the 

 graptolites to be distinct from the Bryozoa* ; and he inclines to the 

 opinion that these organisms were perhaps pelagic forms, floating freely 

 in the sea. The latter idea appears now to be very generally enter- 

 tained ; but there is a somewhat forcible objection to it, which does 

 not seem to have occurred to the holders of this view. It is evident 

 that the compound graptolite structure, or organism, could have pos- 

 sessed in itself no direct powers of locomotion. If free, it must have 

 floated whithersoever the waves and winds directed it ; and, in this 

 manner, it must have drifted, sooner or later, upon coast lines, and 

 there have perished. "We, therefore, still hold to the earlier opinion, 

 that the graptolite mass, in the living state, was attached by its base 

 — and there is nothing in Sir "William Logan's new forms to invali- 

 date this, — to stones, sea-weeds, and other submarine bodies. We 



* See, on this subject, a note by the writer, in vol. i, p. 388, of this Journal. 



