READING RIDDLES OF THE ROCKS 113 
surface of the earth; his great desire is to see 
as much as possible of what may lie beneath. 
So the prospector in search of fossils betakes 
himself to some region where the ceaseless 
warfare waged by water against the dry land 
has seamed the face of the earth with count- 
less gullies and canyons, or carved it into slopes 
and bluffs in which the edges of the bone- 
bearing strata are exposed to view, and along 
these he skirts, ever on the look-out for some 
projecting bit of bone. The country is an 
almost shadeless desert, burning hot by day, 
uncomfortably cool at night. Water is scarce, 
and when it can be found, often has little to 
commend it save wetness; but the collector is 
buoyed up through all this with the hope that 
he may discover some creature new to science 
_ that shall not only be bigger and uglier and 
_ stranger than any heretofore found, but shall 
be the long-sought form needed for the solu- 
tion of some difficult problem in the history 
_ of the past. 
Now collecting is a lottery, differing from 
most lotteries, however, in that while some of 
the returns may be pretty small, there are few 
