SOME AMERICAN MONSTERS. 155 
matrix that the brain-cavity and the openings leading from it 
could be worked out without difficulty. In removing the skull 
from the rock, on the high and almost inaccessible cliff where it 
was found, two or three important fragments were lost; but 
Professor Marsh, after a laborious search, recovered them from 
the bottom of a deep ravine, where they had been washed down 
and covered up. 
It is about twenty-two years since the wonderful forms of life 
sealed up within these Eocene lake-deposits first became known 
to science. Long before then, however, the wandering Indian 
had beer: accustomed to seeing strange-looking skulls and 
skeletons that peeped out upon him from the sides of cafions and 
hills, as the rocks that enclosed them crumbled away under the 
influence of atmospheric agents of change the ceaseless working 
of wind, rain, heat, and cold. To his untrained mind no other 
explanation suggested itself than the idea that these were the 
bones of his ancestors, which it would be highly impious to 
disturb.  Regudescant in pace! So he left them in peace. 
Perhaps he believed in a former race of human giants; if so, 
these would be their bones. Long before Professor Marsh’s 
expeditions, the earliest squatters, trappers, and others used to 
bring back news of marvellous monsters grinning from the ledges 
of rock beneath which they camped. At last these tales attracted 
the notice of some enthusiastic naturalists in the eastern States. 
Professor Leidy obtained a number of bones, from which he was 
able to bring to light an extinct creature at that time unknown 
to science, namely, the Uintatherium. Professor Cope also 
described some extinct animals disinterred by himself from the 
same region. 
But our knowledge of the Dinocerata is chiefly due to 
Professor Marsh, who has despatched one expedition after 
another, and who, after many years of laborious research both in 
the western deserts and in his wonderful collection at Yale 
College, has published a splendid monograph on the subject. 
