196 



The dorsal' fin appears to have had thirteen rays, of which the second was 

 the longest, and from which the others gradually decreased. The anal fin 

 contains fourteen rays. The caudal fin between its two extreme outer and 

 longest rays, inclusive of these, appears to possess twenty rays. 



The ventral carinated spines are twenty-five. Accessory ribs project from 

 the vertebrae and ordinary ribs in the usual manner in the herrings. 



Measurements of the specimen are as follows : 



Lines. 



Total length of tbe fish io 



Length to commeucement of the tail 34 



Depth of body in front of dorsal fin 10 



Deiith at anus 



Length of the head lOi 



Depth of the head 8:^ 



Length of the tail lo" 



Depth of iiedicle of the tail 4 



Distance from snout to couiinenceiuent of dorsal tin 17 



Distance from snout to anus 27 



Clupea alta. 



A slab of shale obtained from the so-called " Petrified Fish Cut,'' and sub- 

 mitted to my examination, contains ten herrings, in which the bones and 

 scales are preserved, and stained of a dark-brown hue. The vertebrae, where 

 broken, exhibit the position of a continuous notochord occupied by hyaline 

 chalcedony that looks like the original substance of the latter itself The 

 most complete and largest of the fossil-fishes is represented of the natural 

 size in Fig. 2, Plate XVII. 



These fishes appear to ])elong to a different species of herring from the 

 former, especially distinguished hy the greater proportionate depth of the 

 body and the more arched dorsal l)order. In most other essential character's 

 the two appear to agree. It has the same number of vertebras and of ventral 

 carinated spines. The fins also, so far as can be determined, appear to con- 

 tain the same number of rays. 



The other specimens on the slab, though smaller, exhil)it the same, or 

 nearly the same, proportionate depth of the body. 



The measurements of the specimen figured are as follows: 



Liiu^s. 



Total length of the fish bO 



Length to commencement of tail 38 



Depth of body in front of dorsal tin Hi 



