752 GEOLOGY. 
years, it seems as if the birds were finding out that the chim- 
neys were no longer suitable places for rearing their young.— 
J. H. Sears, Beverly. Mass. 
GEOLOGY. 
Tue Fossits or CoLtorapo.— The explorations this year have 
been more than usually productive of interesting results. The 
“bad lands” of Colorado have been discovered to be a graveyard 
of a long past period, distinct from that of Wyoming, and to con- 
tain the osseous remains of a great population of beasts, of totally, 
different species and even orders from those of the latter age and 
region. They resemble more nearly those of the White River, of 
Nebraska, but many have been obtained by Prof. Cope not known 
there or elsewhere. So far he has proven the existence of more 
than one hundred species, some represented by thousands of indi- 
viduals. Of these at least seventy species are new to science. 
They range from the size of the mole to nearly that of the ele- 
phant ; sixteen species only are reptiles. 
Many forms of insectivorous animals related to the mole, and 
of very small size, have been procured. The delicacy and mi- 
nuteness of these fossils are surprising. 
Gnawing animals, or rodents, left numerous remains of eighteen 
species, some not larger than the domestic mouse. Some were 
the predecessors of the rabbits, others of squirrels and others of 
mice. 
Of cloven-footed quadrupeds a great many species have been 
found. Some were nearly intermediate in structure between the 
deer and the hog; like the Jatter, they had no horns; they were 
about as large as sheep. Others were about the size of gray squir- 
rels, being the smallest of this class of animals ever discovered. 
Several species of horses were living during the same period, as is 
proven by the bones and teeth which have been discovered. 
Their relative, the rhinoceros, abounded in Colorado, in former 
days, seven species having been procured by Prof. Cope. One 
of the specimens is a perfect skull, with teeth complete and cov- 
ered with the moss-like crystallization seen in the moss agate. But 
the most remarkable monsters of the past, whose existence has 
been disclosed by the present survey, are a series of horned species 
related to the rhinoceros, but possessing some features in which, 
< Mirine to Prof. Cope, they resembled the elephant. They 
