336 Annals of the Carnegie Museum. 



Family Conocardiid.e Neumayr. 

 Genus Conocardium Brongniart. 



12. Conocardium beecheri Raymond. (Plate XXX, figures 4-10.) 



Conocardium beecheri Raymond. American Journal of Science (Ser. 4), Vol. XX, 

 1905. P- 374- 



One of the unexpected discoveries made while collecting at Valcour 

 Island was a small Conocardium which was found in great numbers on 

 Sloop Island, a rock about one-fourth mile east of Valcour Island- 

 The writer has since found it on the main island of Valcour, and at 

 Chazy but it is very rare at both these places. Twenhofel and 

 Schuchert recently found it on the Mingan Islands.^i 



Conocardium beecheri is the oldest representative of the genus. 

 Conocardium immaturum Billings, from the Black River at Pauquette's 

 Rapids on the Ottawa River, is of about the same size as our specimens, 

 but differs from them in having a broader and shorter anterior wing, 

 and a smooth posterior wing. The only other Ordovician species is 

 Conocardium {Pleurorhynchus) antiqua Owen, from the Ordovician 

 at Lower Fort Garry, on the Red River of the North. This sp-^cies is 

 not well known, as no description has been published, and only a single 

 imperfect specimen figured. 



Eopteria typica and Euchasma blumenbachia, both described by 

 Billings, have somewhat the form of Conocardium, but a different 

 hinge-structure. They are not well known. Dal), in the American 

 edition of Zittel's Paleontology, places these genera with doubt in 

 the family Cardiolidce. They are believed by others to be Crustacea. 



Description. 



Shell small but robust, with long anterior and short posterior wings. 

 The region of greatest convexity is along the mid-line of the shell, 

 the convexity decreasing gradually to the anterior wing and rather 

 abruptly to the posterior one. The anterior wing is long, with a 

 straight lower margin. The posterior wing is short and narrow, 

 joining the shell at a large angle. The surface is marked by seven or 

 eight large plications on the anterior wing, fifteen to twenty smaller 

 ones on the body of the shell, and three or four very large ones on the 

 posterior wing. 



^^ Bull. Geol. Soc. America, Vol. 21, p. 692, 1910. 



