1870.] '^^^ [Cope. 



There are portions of five individuals on the slab of slate, but none pre- 

 sent a clear cranium. This slab represents that portion of the stratum 

 which is highly carbonaceous, portions of it thrown into the fire burn 

 freely. Dr. Hayden, who has brought numerous specimens from this 

 locality, informs me that the laminae exhibit great numbers of these little 

 fishes. No doubt the carbonaceous character of the shales is due to the 

 decomposition of their bodies. The character of the species, as well as 

 nature of the deposit, and mode of preservation, remind one strongly of 

 the Cyprinodon meyeri, of Agassiz, from the neighborhood of Frankfort a. 

 M. That species differs especially in presenting 18 Anal radii. 



Some of the specimens above described were obtained and preserved for 

 scientific study, by David B. Collier, formally United States District At- 

 torney for the Territory of Wyoming. 



From a Tertiary deposit on the upper waters of Green River, Wyoming 

 Territory, from a laminated calcareous rock similar in color and appear- 

 ance to the clay beds of Mount Lebanon and Mount Bolca. The first in- 

 dication of the existence of this deposit was brought by Dr. Jno. Evans, 

 who obtained from it a Clupeoid, which was described by Dr. Leidy, as 

 Clupea humilis (Proc. Acad. Nat. Sci., Phila., 1856, p. 256). One of the 

 blocks contains the remains of two small shoals of the fry, probably of 

 Clupea humilis, which were caught suddenly by a slide or fall of calca- 

 reous mud, and entombed for the observation of future students. They 

 must have been taken unwares, since they lie with their heads all in one 

 direction as they swam in close bodies. One or two may have had a mo- 

 ment's warning of the catastrophe, as they have turned a little aside, but 

 they are the exceptions. The fry are from one-half to three-quarters of 

 an inch long and upwards. 



True herring, or those with teeth, are chiefly marine, but they run into 

 fresh waters and deposit their spawn in the Spring of the year, and then 

 return to salt waters. The young run down to the sea in Autumn and 

 remain there till old enough to spawn. The size of the fry of the Rocky 

 Mountain herring indicates that they had not long left the spawning 

 ground, while the abundance of adults suggests they were not far from 

 salt water, their native element. To believe, then, that the locality from 

 which the specimens were taken was neither far from fresh, nor far from 

 salt waters, is reasonable; and this points to a tide, or brackish inlet or 

 river. Lastly, the species of Cyprinodon inhabit also, tide and brackish 

 waters. Most of the species of the family, as well as of the genus, are in- 

 habitants of fresh water; but they generally, especially the Cyprinodons 

 proper, prefer still and muddy localities, and often occur in water really 

 salt. This habitat distinguishes them especially from Cyprinidae (Min- 

 nows and Suckers) and Pike. 



The material which composes the shales indicates quiet water, and not 

 such as is visually selected by herring for spawning in; while the abund- 

 ance of adult Clupeas indicate the proximity of salt water. 



This is far from a satisfactory demonstration of the nature of the water 

 which deposited this mass of shales, but is the best that can be obtained 

 with such a meagre representation of species. 



