TRIASSIC MAMMIFER. 
383 
Heer to have the nearest affinity to tliose of the European 
Keiiper. 
The equiseta are very commonly met with in a vertical 
position more or less compressed perpendicularly. It is 
clear that they grew in the places where they are now 
buried in strata of hardened sand and mud. I found them 
maintaining their erect attitude, at points many miles apart, 
in beds both above and between the seams of coal. In order 
to explain this fact, we must suppose such shales and sand¬ 
stones to have been gradually accumulated during the slow 
and repeated subsidence of the whole region. 
The fossil fish are Ganoids, some of them of the genus 
Catopteriis^ others belonging to the liassic genus Tetragono- 
lepis {^chmodus)^ see Fig. 
376, p. 358. Two species 
of Mitomostraca called JEs- 
theria are in such profusion 
in some shaly beds as to 
divide them like the plates 
of mica in micaceous shales 
(see Fig. 409). 
These Virginian coal- 
measures are composed of 
grits, sandstones, and 
shales, exactly resemblin 
Fi<r. 409. 
. Triassic coal-shale, Richmond, Virginia, 
those of older or primary a. EstheHa ovata. b. Young of same. c. Nat- 
date in America and Eu- uralsizeofa. d. Natural size of &. 
rope, and they rival, or even surpass; the latter in the richness 
and thickness of the coal-seams. One of these, the main seam, 
is in some places from 30 to 40 feet thick, composed of pure 
bituminous coal. The coal is like the finest kinds shipped at 
Newcastle, and when analyzed yields the same proportions 
of carbon and hydrogen—a fact worthy of notice, when we 
consider that this fuel has been derived from an assemblage 
of‘plants very distinct specifically, and in part generically, 
from those which have contributed to the formation of the 
ancient or palaeozoic coal. 
Triassic Mammifer. —In North Carolina, the late Professor 
Emmons has described the strata of the Chatham coal-field, 
which correspond in age to those near Richmond, in Virginia. 
In beds underlying them he has met with three jaws of a 
small insectivorous mammal which he has called Dromatlie- 
riiim sylvestre^ closely allied to Spalacotheriimi, Its near¬ 
est living analogue, says Professor Owen, “is found in Myr- 
mecobius; for each ramus of the lower jaw contained ten 
small molars in a continuous series, one canine, and three 
