S«4 PALAEONTOLOGY OF NEW- YORK. 



son of specimens from more soutliern localities, with those of New- York, shows a 

 large proportion of new species; and it now appears probable that tlie number of 

 American species of Graptolithus previously known (about twenty), will soon be 

 increased by an equal number of new ones. 



Ijocality and formation. Point Levy, Canada : Hudson-river group. 



In addition to the species above noticed, tlie following are published in the same 

 Report for 1857 : 



GRAPTOLrrHUS FLEXILIS, 



GRAPTOLirnus indentds, 



Besides these species of Graptolithcs, there are some other forms 

 in the Canadian collection, separated by the writer under the name 

 Phyllograptus, as follows : 



Genus Piiyllograptis. 



J^ND consisting of simple foliate expansions, celluliferous or serrated 

 upon the two opposite sides : margins with a mucronate extension from 

 each cellule ; or of similar foliate forms united rectangularly by their 

 longitudinal axes, and furnished on their outer margins with similar 

 cellules or serratures, the whole supported on a slender radicle. 

 These bodies, which usually appear upon the stone in the form of simple leaf-like 

 expansions, may possibly have been attached in groups to some other support; but 

 the form of some of tliem, and the character of the projecting radicle at the base, 

 indicate that we have the entire frond. These forms furnish perhaps the best illu- 

 stration of all the Graptolitidea, of the lesser development of the cells at the base, 

 and their gradual expansion above until they reach the middle or upper part of the 

 frond. Many of them diminish from the centre upwards; and rarely the cells are 

 more developed above the centre, reversing the usual form, and leaving the nar- 

 rower part at the base. 



