296 FOSSIL GEOLOGY OP UNITED STATES. 
mus), two species of elephant (elephas primigenius), 
the megatherium, megalonyx (Jeffersomi), three spe- 
cies of the ox family, the fossil elk, and the walrus. 
Of living species found fossil there are the horse, 
bison, and three or four species of deer. The sit- 
uations in which these have been found have been 
either very recent undisturbed alluvial bogs, or a 
slightly-disturbed marshy deposite, like Big Bone 
Lick, neither of them covered by the general dilu- 
vium ; thirdly, boggy beds containing lignite referri- 
ble to an ancient alluvium, covered by diluvial sand 
and gravel ; and, lastly, the floors of caves, buried 
to a very small depth with earth not described. 
The largest collections of bone-remains occur in 
boggy grounds called licks, affording salt, in quest 
of which the herbivorous animals, wild and domes- 
tic, enter the marshy spot and are sometimes mired. 
The most noted of these spots is Big Bone Lick, in 
Kentucky, occupying the bottom of a boggy valley, 
kept wet by a number of salt-springs, which rise 
over a surface of several acres. The spot is thus 
described by Mr. Cooper : " The substratum of the 
country is a fossiliferous limestone. At the lick 
the valley is filled up, to the depth of not less than 
30 feet, with unconsolidated beds of earth of va- 
rious kinds. The uppermost of these is a light 
yellow clay, which, apparently, is no more than the 
soil brought down from the high grounds by rains 
and land-floods. In this yellow earth are found, 
along the water-courses, at various depths, the 
bones of buff'aloes and other modern animals, many 
broken, but often quite entire. Beneath this is an- 
other thinner layer of a difl*erent soil, bearing the 
appearance of. having been formerly the bottom of 
a marsh. It is more gravelly, darker coloured, 
softer, and contains remains of reedy plants, smaller 
than the cane so abundant in some parts of Ken- 
tucky, with fresh- water mollusca. In this layer, and 
sometimes partially imbedded in a stratum of blue 
