446 Fossils of the Chazy Limestone. 



or five lines ; the greatest width is at about one- third or one fourth 

 the length from the front, and is either equal to or a little less 

 than the length. 



This species resembles Camerella hemipUcatus (Hall, S.p.) ; 

 but is always smaller and not so globose. 



Locality and Formation — Mingan Islands. Chazy Limestone. 



Collectors. — Sir W. E. Logan and J. Richardson. 



Bryozoa. 5 species. 



Three of the species appear to belong to Fenestella or Poly- 

 pora ; the others to Ptylodictya. They require further examina- 

 tion and comparison before they can be described. 



Lamellibranchiata. 17 Species. 



These fossils are rare in the Chazy limestone, yet the species 

 appear to be somewhat numerous. I think I can make out 17 

 species belonging to Qtenodonta, Cyrtodonta y Vanuxemia, Modio- 

 lopsis, and probably two or three other genera. 



As the specimens consist mostly of casts, they must remain 

 undescribed until better can be procured. The following are all 

 that I have determined up to the present date : — 



Ctenodonta nasuta. (Hall, S.p.) 

 Tellinomya nasuta. (Hall.) Ctenodonta nasuta. (Salter.) 

 This well known species occurs in the Chazy sandstone at Lac 

 Aurau River above the River Rouge and also at the Mingan 

 Islands in the Chazy limestone. 



MODIOLOPSIS PARVITJSCULA. (N.S.) 



This species closely resembles M. modiolaris (Conrad) ; but is 

 always less than half the size of that species. It occurs in the 

 Chazy limestone at Montreal, near Cornwall, at the Mingan 

 Islands, on the Islands at Lake Huron, and also at Punk Island, 

 Lake Winnipeg. 



Cyrtodonta breviuscula. (N.s.) 



Description. — Sub-rhomboidal ; hinge line straight elevated J 

 anterior extremity broadly rounded ; posterior extremity oblique- 

 ly truncated and somewhat straight from the hinge line to within 

 one- third the height from the posterior ventral angle, which is 

 rather narrowly rounded ; ventral margin gently concave about the 

 middle ; umbpnes small, obtuse, near the anterior extremity . 

 valves rather strongly couvex, most prominent about the middle 



