72 REVIEWS NEW SPECIES OP LOWER SILURIAN FOSSILS. 



by Mr. Billings, several are referred to new genera. The limestone of 

 -Anse au Loup on the north shore of the Straits of Belle Isle, has 

 . furnished two peculiar corals (or sponges) somewhat resembling^e^)-om 

 or zaphrentis, but considered by Mr. Billings to belong to a distinct 

 genus, which he names Areheocyathus. The form is turbinate, simple 

 or aggregate ; the cup deep, and composed apparently of two walls 

 with connecting radiating lamellae, between which, poriferous tissue is 

 distributed. The inner wall, according to . Mr. Billings, appears to 

 have been traversed by pores, affording a communication between the 

 inside of the cup and the spaces filled with the interseptal tissue. One 

 of the species is named A. Atlanticus, .the other ^. MinganensiS' 

 The latter passes upwards into the calciferous group, and is the form 

 previously described by the author (from internal casts) as a petraia. 

 Amongst the Brachiopods, which include species of Obolus, Orthis, 

 Orthisina, and Camerella, there is also a newly-determined genus. On 

 this, Mr. Billing bestows the name of Obolella, from its relationship 

 to Obolus. In the latter, the smaller ends of the central pair of muscular 

 . impressions belonging to the ventral valve are directed downwards a,nd 

 towards each other, whilst in Obolella, according to Mr. Billings, the ffi- 

 verse of this occurs. The shell is of the ordinary calcareous character,and 

 does not exhibit the dark lustrous appearance common to most species of 

 Obolus. Two species are enumerated ; but one of these, O. cingulata, 

 from Anse au Loup, and from Swanton, Vermont, Mr. Billings con- 

 siders may be still generically distinct. 



The trUobites of these Potsdam rocks are more especially interest- 

 ing. In addition to the much discussed Paradoxides, first discovered 

 in the Potsdam beds of Vermont, and of which examples have since 

 been found at Anse au Loup, Mr. Billings describes no less than five 

 species of the genus Conocephalites, and two belonging to Bathyurus. 

 The first of these genera, it is now well-known, is eminently charac- 

 teristic of the Primordial Zone of Europe. The occurrence of the 

 Paradoxides or Oleni at the distant locality of Anse au Loup, is, a. 

 fact of much importance in settling the true position of the Vermont 

 Strata. Their discovery is due to Mr. Richardson, of the Geological 

 Survey, who has traced out on the north shore of the Straits of Belle 

 Isle a complete sequence of the lower fossiliferous beds. 



At the close of this publication, descriptions are given of some n^w 

 fossils from the Calciferous, Chazy, Black Eiver, and Trenton forma- 

 tions. The more important of these comprise several sponges. 



