CAUDA-GALLI GRIT. 



171 



The agricultural characters of this rock are unimportant; and no mineral, excepting a 

 jaspery iron ore, has hecn found in it (See Vanuxem's Report, pp. 125-6). 



Fig. 99. 



§ 6. Cauda-galli grit (PI. xx. Sec. 1, 5, 6). 

 A spiral vegetable fossil, which, when flattened, appears like a cock's tail with its long 

 flowing feathers, gave origin to the name of this rock.* It is a dark bluish sandstone 

 beneath, with a quantity of argillaceous matter ; and brown above, where this singular 

 fossil abounds, though the lower part is not destitute of them, and they are even in some 

 places impressed upon the upper surface of the Oriskany sandstone. The rock breaks 

 down under the action of the weather : the first change in its integrity consists in the sepa- 

 ration of the surface portion into short imperfect columns ; and these continually diminish, 

 until they pass into an imperfect gravel. It is thin-bedded throughout the whole rock : 



• See Vanuxem's Report, p. 128. 

 22* 



