FOSSIL FISHES. Zl 
some light on the manner in which they were entombed. This locality is 
near the western margin of the Triassic area where strata of shaly sand- 
stone rest upon coarse conglomerate, showing the different conditions which 
prevailed at the same locality within a limited interval of time. Certain 
layers of the shales are crowded with fishes, a slab a yard square carrying 
sometimes a half dozen or more. Some of these are dismembered, consist- 
ing of a shapeless aggregate of scales and bones, but most are nearly per- 
fect; and the number found at about the same level, with their perfection 
of preservation, seem to show that the generation inhabiting that portion 
of the Triassic basin at a certain time were somewhat suddenly killed and 
sunk to the bottom, where they were soon covered with the accumulating 
sediment and were thus preserved. The layers of the shale which contain 
the largest number of fishes are impregnated with bituminous matter, burn- 
ing for a time when thrown into the fire, and when struck with a hammer 
giving off a peculiar odor. Similar fish beds are known to exist at Pomp- 
ton, Plainfield, and beneath the trap of the Palisades above Hoboken, and 
it seems probable that the great mortality which strewed the bottom of the 
basin at times with dead fishes was the result of some phase of the voleanic 
action which poured out the trap masses of the Palisades and Newark 
Mountains. 
Fishes seem to be equally abundant in the Connecticut River basin. 
At Durham, Conn., and Turner's Falls, Mass., they are particularly numerous 
and well preserved, while they have also been obtained at Middletown, Sud- 
bury, Chicopee, Amherst, and Hadley’s Falls. Collections made at all these 
localities have been studied by me, and among them I have identified with 
more or less confidence about twenty-five species. ‘To the list of the species 
of Catopterus and Ischypterus enumerated by the Messrs. Redfield perhaps 
as many more have been added, and two genera which they do not seem 
to have met with, viz, Dipluwrus Newb. and Ptycholepis Ag. These will be 
found figured and described in another part of this memoir. In the revision 
of the group of fishes studied by the Messrs. Redfield access has been 
had to the specimens left by Mr. W. C. Redfield, most of which were do- 
nated to the Peabody Museum at Yale College. The collection contains 
many types of the species described by the Messrs. Redfield, but unfortu- 
