38 
EOCENE FISHES. 
malian teeth accompanying tliose of the Sharks are not transported from 
another formation, and there is nothing to show that the origin of the two was 
different. A similar state of things exists in the siderolitic Eocene beds of 
the canton Vaud, Switzerland, where Mammalian bones are mingled with 
Sharks’ teeth. M. I^a Harpe remarks respecting these, that there is nothing 
to show that these teeth are not in place in the Eocene beds, and no evi¬ 
dence that they have been transported. The genera of Sharks observed 
by me in New Mexico are still existing (Lamna, Galeocerdo, &c.), and 
are strictly marine. The cause of their occurrence in beds usually 
supposed to be lacustrine cannot be stated; but, as Mollusca are almost 
wanting from the latter, there is no evidence to disprove the supposition 
that the ancient lake had open communication with the ocean, and that its 
waters were, at one time at least, more or less salt. 
The species, so far as determinable from the injured state of the speci¬ 
mens, are known Cretaceous and Tertiary forms. They are Lamna texana, 
Roemer, and an undetermined Lamna; an Oxyrliina or Otodus, undeter¬ 
mined; Galeocerdo pristodontns and G. fadimcus; and a fragment of a large 
tooth, with straight denticulate edge. These teeth are figured on pi. xxii, 
figs. 18-19. The remains of Lepidosteidce come next in order. 
GINGLYMODL 
Two genera of this order are known from the Tertiary formations of 
North America; Clastes, from the Eocene, and Pneumatosteus, Cope, from 
tho Miocene beds. The former has only been found in the Rocky Mount¬ 
ain region, the latter in the East, in North Carolina. The existing species 
are confined to North and Central America, and belong to two genera,, 
dosteus and Atractosteus. 
CLASTES, Cope. 
Annual Report U. S. Geol. Survey. Terrs., 1872, p. C33. 
Clastes aganus, Cope. 
Plate xxiii, figs. 10-29. 
This Garfish is represented by a number of fragments of the cranium, 
several vertebrae, and numerous scales, belonging to one individual. Less 
