READING RIDDLES OF THE ROCKS 131 
instance, when vertebre that seem illy adapted 
for carrying the weight of a land® animal are 
found in company with huge limb-bones and 
massive feet we may feel reasonably certain 
that their owner passed at least a portion of his 
time on terra firma. 
So much for the probabilities as to the cov- 
ering of animals known to us only by their fos- 
sil remains ; but it is often possible to go be- 
yond this, and to state certainly how they were 
clad. For while the chances are small that 
any trace of the covering of an extinct animal, 
other than bony plates, will be preserved, Nat- 
ure does now and then seem to have relented, 
and occasionally some animal settled to rest 
where it was so quickly and quietly covered 
with fine mud that the impression of small 
scales, feathers, or even smooth skin, was pre- 
served; curiously enough, there seems to be 
scarcely any record of the imprint of hair. 
Then, too, it is to be remembered that while 
the chances were very much against such pres- 
ervation, in the thousands or millions of times 
creatures died the millionth chance might come 
uppermost. 
