428 GEOLOGICAL SURVEY OF THE TERRITORIES. 



M. 



Total length No. 1 0.0743 



Cranium to supra-clavicle 018 



Length to base D. I. 029 



Length to eud vertebral column 06 



Length of A. II .008 



Length of cranium No. 2 0175 



Length to preoperculum 012 



Length to D. 1 0275 



Length to A. I 043 



Five more or less complete specimens of this fish were obtained by- 

 Lucius E. Eicksecker from the Green Eiver shales, and I dedicate it to 

 him in recognition of his interesting discoveries in this department. 



Its difference from E. levatus is seen in the more anterior position of 

 the dorsal fin, more numerous vertebrae, &c. 



ERISMATOPTERTTS LEVATUS, (COPE.) 



(Cyprinodon levatus, Cope; Proceed. Aiuer. Pliilos. Soc., 1870, p. 382.) 



Anterior margin anal fin commencing a little behind opposite the 

 posterior margin of the dorsal. Vertebrae 11 — 14 — 5, seven between the 

 interneural and interhsernal bones of the dorsal and anal fins. Eadii D. 

 8 ; A. II, 8 ; V. 8. Caudal fin deeply furcate ; first anal ray strong. 

 General form elongate, the greatest depth contained three times in the 

 length between the scapular arch and the basis of the caudal fin. Scales 

 preserved, small : seven longitudinal series above, and seven below the 

 vertebral column, probably two rows concealed by it. The caudal peduncle 

 is but little contracted. Length from scapular arch to extremity of 

 caudal, M. .0335 ; depth at origin dorsal fin, M. .008. 



Total length No. 2 0.055 



Length of cranium 013 



Length to basis D. I 0232 



Length to basis A. 1 033 



Length to basis V. I. 0205 



Length to basis caudal 04G6 



Depth at D. I 01 



Depth of caudal peduncle 0058 



There are many individuals on the slabs of slate, some of them per- 

 fectly preserved. Many of these slabs represent that portion of the 

 stratum which is highly carbonaceous, portions of it thrown into the 

 fire burning 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 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 specifically from this one in jn-esenting 18 anal radii. 



Some of the specimens above described were obtained, and preserved 

 for scientific study, by L. E. Eicksecker. 



