1908] Chazy Pelecypoda 107 



nearly 2^ inches). The greatest length of the right valve 

 of M. parviiiscula from Cornwall (fig.l) is 24 mm. (or a 

 little less than an inch) ; and that of one of the largest valves 

 of a specimen of the same species from Punk Island (fig. 

 2) is about ii mm. (or an inch and a quarter). 



M. parviiiscula is rather an inappropriate name for 

 the species for which it was proposed, as it is by no means 

 the smallest of the genus. In the Museum of the Survey 

 there are two specimens of M. faba (Conrad, 1842), from 

 the Black River limestone at Paquettes Rapids, that are 

 onlv 4 and 5 mm., respectively, in their maximum length. 



Cyrtodonta breviuscula, Billings (PI. III. fig. 3). 



The type and only known specimen of this species, 

 in the Museum of the Geological Survey of Canada, is the 

 left valve figured on Plate III. It is said to have been 

 collected b}^ Mr. Billings from the "Chazy sandstone three 

 miles east of the city of Ottawa, half a mile back from the 

 river." 



Vanuxemia Montrealensis, Billings. 



The types of this species, from the "Chazy limestone 

 on the Island of Montreal and near L'Orignal," were 

 collected b}' Sir W. E. Logan and Dr.R. Bell. In regard to 

 this species Mr. Billings writes, "I have placed it in the 

 genus Vanuxemia provisionally, but it may be necessar}^ 

 hereafter to remove it to some other genus." Ulrich places 

 Vanuxemia in his family C yrtodontidoe , but it has long 

 seemed to the writer that V. Montrealensis, with its thin 

 test and compressed mytiloid form, is rather referable to 

 the Anthony chiidce . In 1903, Dr. H. M. Ami made an 

 interesting collection of fossils from the Chazy limestone 

 at Van Home Avenue, Montreal. Among these fossils 

 there are twenty-five or more that appear to be referable 

 to V. Montrealensis, though most of them are only imperfect 

 and badly preserved casts of the interior of single valves. 

 If these specimens are correctly identified with V. Mon- 

 trealensis, then, in the writer's judgment, that species must 

 belong to Ulrich's genus Clionychia, there being, apparently, 

 no bvssal opening as in Psilonychia. 



In an Appendix to Dr. R. W. Ells' Report on the Geology 

 and Natural Resources of the Area included in the Map of the 

 City of Ottawa and vicinity, published in 1889, in the Annual 

 Report, New Series, Vol. XII, of the Geological Survey of 

 Canada, Dr. H. M. Ami records the occurrence of Vanuxemia 



