1890.] Geology and Paleontology. 767 
zone has shown one limited horizon, at least, that is widely distributed 
in Europe which is also readily recognized in the state of New York.” 
The Echinodermata of the Carboniferous—C. R. K f 
in the Am. Jour. Sci., Sept. 1889, discussing the Carboniferous 
Echinodermata of the Mississippi basin, recapitulates as follows : 
It appears that (1) the most characteristic faunal group was pre- 
eminently dual in its general aspect, the Crinoidea greatly predomi- 
nating during the first part and the Blastoidea during the latter por- 
tionjof the period; (2) that a large proportion of the genera of Echi- 
noderms became extinct toward the close of the Keokuk; (3) that of 
the Crinoidal genera represented in the St. Louis and Chester, nearly 
one-half of the number did not occur in the earlier epochs; (4) that 
among the Crinoidea in general the abrupt and extensive differentia- 
tion in certain anatomical features toward the end of the Keokuk 
are suggestive of decided changes in the biological and physical con- 
ditions of environment ; (5) that the faunas of the Burlington and 
Keokuk are very closely related genetically, the two being practically 
continuous ; (6) that if the members of the Lower Carboniferous of the 
Mississippi are to be synchronized with the two divisions of the Ap- 
palachian Lower Carboniferous, the line of demarkation is far more 
apparent at the close than at the beginning of the Keokuk epoch. 
A Recent Find of Castoroides.—Interest attaches to a 
recent find of Castoroides ohioensis, since the species, though known 
since 1838, has heretofore been studied from rather meagre fragments. 
This find, which was made in Indiana is well nigh a complete skeleton. 
The parietal and occipital regions of the skull are wanting, but they 
have been well studied already. The dentition, however, is perfect, 
both above and below, and is more fully developed than in the Clyde 
skull found in 1840. The vertebre in front of the pelvis are all 
present, except two of the dorsal and four of the cervical. The two 
. most important, the atlas and axis, were found. 
The shoulder-blades, clavicles, and fore-legs, minus the feet, show an 
animal powerfully developed anteriorly. The tail is proportionally 
about as long as that of the beaver. Everything about it indicates 
that it was an important and powerful member. In the middle and 
more posterior region the transverse processes are broad, heavy, and 
bifurcate, as in the beaver, but relatively not nearly so long. If its 
tail was flat it was not so wide as that of the beaver. It was five- 
toed and plantigrade. 
