26 



PAI.aONTOLOGV OF NEW-YORK. 



ICHNOPHYCUS. 



Among the numerous curious impressions and remains of plants and other bodies in the shaly 

 sandstones of this group, these are interesting from their similarity in form to the Ornithicnites 

 of the New Red Sandstone ; but since we have no evidence of the existence of such animals 

 at this period, I have proposed a name significant of their form, and more for the purpose of 

 attracting attention to the fact of their occurrence, than for the purpose of deciding their true 

 relations, which cannot be done with the meagre materials we possess. 



415. 1. ICHNOPHYCUS TRIDACTYLUS («.«;).). 



Pl. X. Fiff. 7 a, b. 



Impressions tridactyle, apparently in series one before the other ; substance of the fossil 

 resembling that of other species of marine plants. 



The only specimens seen are those represented on Plate X, fig. 7 a, b. The specimen 7 a 

 represents the surface of a slab, with two tridactyle impressions arranged as in the figure. The 

 impressions are indented, and the laminse depressed around them : the extremities are pointed, 

 the central one being longest. They resemble very closely the tracks of birds in the sandstone 

 of the Connecticut valley, but we have no evidence of the existence of birds at the period of 

 the Clinton group. 



The specimen 7 6 is in relief upon the under surface of a slab of shaly sandstone, and appears 

 like a substance itself rather than a cast of an impression of this form. 



It will be observed that both the impressions on 7 a, and the one in relief 7 i, present an 

 emargination behind, in which they differ from most of the Ornithicnites of the Connecticut 

 river ■^'alley. 



Whatever these curious impressions may be proved to be, they are subjects of interest ; and 

 further investigation may throw light upon them, to enable us to decide their true relations. 



Position and locality. Blackstone's quarries, associated with numerous species of marine 

 plants. 



TRACKS OF GASTEROPODA, CRUSTACEA, OR OTHER MARINE ANIMALS. 



Among the evidences of the existence of organic beings, and of the condition of the ocean 

 bed during the deposition of the strata composing this group, may be mentioned the occurrence 

 of the tracks of various animals, some of which, as they passed over or just beneath the surface 

 of the sand, have left a continuous furrow or trail, while others present the character of distinct 

 and separate footprints. These trails, though not organic in themselves, are nevertheless so in- 

 teresting that I present them in connexion with the other evidences of organic life at this period. 

 From the character of the surfaces of the arenaceous beds in which they occur, I am inclined 

 to the belief that many of them were made while the bed was exposed above water, and most 



