COPE ON ICHTHYIC FAUNA OF THE GREEN RIVER SHALES. 819 
Number of species. 
This lo- | Entire for- 
cality. mation. 
Da ped os lOssS: 55 .c. lew Seaweeds sey se oA es ee ees 1 2 
Diploinystus sss. ya cseihoaasis clon etacios de Sead oo SU ameto.ees 5 pe 
EriSM GhOpter use oc scigee cece dd cwiepinetas screws weicie weisiwe acca Gaieeier 1 3 
Am phi plage s2csans says duis Sociges ateiet raise talaietheeuieiansionas Sacciex 1 1 
ASINGODS cs:ccccieis de shea wie wage ocala cisice ee eisldneaisicnnviers Hew aries 1 3 
Midpl0StiSiveis cass cece ceo scice seu ceed messi casiecciteidieee case acct 4 4 
Priscucara...-....- else Ree gio es: beled ae wis Sania S Hie ee sesi% se-s0a cat0 3 3 
16 23 
The Herring (Diplomystus) exceed all others in number of species and 
~ individuals. One of the species (D. humilis) is more abundant than all 
the other species of all genera put together. Long after these come, in 
point of numbers, the more typical spinous-rayed species, which doubt- 
less preyed upon them. The following speciesare represented by but one — 
individual each :—Diplomystus dentatus, Erismatopterus endlichti, Am- 
*. phiplaga brachyptera, Asineops pauciradiatus, Mioplosus abbreviatus, M. 
beanti, and Priscacara cypha. 
A consideration of the fauna with the additional light derived from 
this accession of new material is of some value in connection with the 
question of the relation of this formation to the oceans and lakes of the 
Eocene period. I have heretofore expressed the opinion that the Green 
River water-area in which the shales were deposited may have had, 
like the Wasatch Lake of New Mexico, connection with the sea, and 
pointed out the broad distinction between its fish-fauna and that of the 
undoubtedly land-locked lakes of the South Park of Colorado and of 
Elko, Nev. The fishes of the latter formation are nearly.related to — 
fresh-water types only, and to those at present inhabiting North Amer- 
ica. On the other hand, the Green River Shales contain two striking 
representatives of families which do not now exist in North America, 
and very rarely in any of the northern realms of the earth. These are the 
Osteoglossidw, whose genera are all fresh-water, and the Pharyngo- 
gnathi, with ctenoid scales. Some of these are marine (Pomacentride), 
and others are fresh-water (Chromidide). The Green River genus Pris- 
cacara is, in some respects, more nearly allied to the latter than the for- 
mer family, but not entirely so. 
The remaining genera (excepting Asineops) correspond to existing 
North American genera, viz :—Diplomystus, to Clupea ; Erismatopterus 
and Amphiplaga, to Aphredodirus ; and Mioplosus, to Labrax. The first- 
and last-named recent genera are anadromous, and Aphredodirus exists 
in tide-water; it has also been found near the Great Lakes. We look 
for further material to throw light on the question of possiblé marine 
eommunication with the Green River lake. 
