NAPLES FAUNA IN WESTERN NEW YORK, PART 2 309 



face regularly convex and distinctly elevated in the umbonal region. Orna- 

 ment consisting of about 19 sharply defined, flattened ribs, which near the 

 pallial margin are not so broad as the interspaces. These ribs are divided 

 on their summit by a low median depression, which leaves the edges promi- 

 nent, and of the same character as in Praecard. duplicatum, though 

 their duplication is not so pronounced. On the posterior cardinal slope, 

 which is depressed and flattened, the ribs retain a simple character, while 

 the broad anterior slope is quite smooth. Traces of a minute concentric 

 striation are seen on the surface of internal casts. An undistorted speci- 

 men has a length of 10 mm and width of 9.5 mm. 



This species is readily distinguished, and, like Praecard. dupli- 

 catum, shows an affiliation to Buchiola in its ornamentation. 



Beushausen mentions and figures a valve of Praecardium sp. 1 which, 

 though larger than Praecard. multicostatum, resembles it in outline 

 and in the number of its plications. This, like the specimens of Praecard. 

 duplicatum, is from the Clymeniakalk of the Enkeberg. 



Habitat. Genesee province ; Chautauqua subprovince. In the soft 

 shales in the gorge of Walnut creek, Forestville, Chautauqua co. 



pueixa Barrande. 1881 



Plate 11, fig. 26-29 



Species of this genus occur occasionally in the gray and black shales 

 of the Portage formation and the black shales of the Genesee. The speci- 

 mens in our collections serve solely to indicate the presence of distinct 

 forms, but are not well enough preserved to justify an attempt at descrip- 

 tion. There are 



1 A small orbicular species having about the dimensions and outline 

 common to Ontaria sub orbicularis, with 25 to 30 coarse plications, 

 which has been found in the gray shales at the base of the Naples beds on 

 Canandaigua lake. 



2 A large and quite oblique species with broad, coarse ribs, 28 to 30 in 

 number, on the anterior slope and finer ribs posteriorly, which has a hight 



*Op. at. p. 304, p l. 31, fig. 5. 



