382 
ELEMENTS OF GEOLOGY. 
the three-jointed and five^jointed toes placed alternately out¬ 
ward, first on the one side, and then on the other. In some 
specimens, besides impressions of the three toes in front, the 
rudiment is seen of the fourth toe behind. It is not often 
that the matrix has been fine enough to retain impressions 
of the integument or skin of the foot; but in one fine speci¬ 
men found at Turner’s Falls, on the Connecticut, by Dr. 
Deane, these markings are well preserved, and have been 
recognized by Professor Owen as resembling the skin of the 
ostrich, and not that of reptiles. 
The casts of the foot-prints show that some of the fossil 
bipeds of the red sandstone of Connecticut had feet four times 
as large as the living ostrich, but scarcely, perhaps, larger 
than the Dinornis of New Zealand, a lost genus of feathered 
giants related to the Apteryx, of which there were many spe¬ 
cies which have left their bones and almost entire skeletons 
in the superficial alluvium of that island. By referring to 
what was said of the Iguanodon of the Wealden, the reader 
will perceive that the l3inosaur was somewhat intermediate 
between reptiles and birds, and left a series of tridactylous 
impressions on the sand. 
To determine the exact age of the red sandstone and 
shale containing these ancient foot-prints, in the United States, 
is not possible at present. No fossil shells have yet been 
found in the deposit, nor plants in a determinable state. The 
fossil fish are numerous and very perfect; but they are of a 
peculiar type, called Iscliypterus^ by Sir Philip Egerton, from 
the great size and strength of the fulcral rays of the dorsal 
fin, from strength, and irrspoy^ a fin. 
The age of the Connecticut beds can not be proved by di¬ 
rect superposition, but may be presumed from the general 
structure of the country. That structure proves them to be 
newer than the movements to which the Appalachian or Al¬ 
leghany chain owes its flexures, and this chain includes the 
ancient or palaeozoic coal - formation among its contorted 
rocks. 
Coal-field of Richmond, Virginia. —^In the State of Virginia, 
at the distance of about 13 miles eastward of Richmond, the 
capital of that State, there is a coal-field occurring in a de¬ 
pression of the granite rocks, and occupying a geological po¬ 
sition analogous to that of the New Red Sandstone, above 
mentioned, of the Connecticut valley. It extends 26 miles 
from north to south, and from four to tw'elve from east to 
west. 
The plants consist chiefly of zamites, calamites, equiseta, 
and ferns, and, upon the whole, are considered by Professor 
