READING RIDDLES OF THE ROCKS 117 
of rock, in order that all parts may be pre- 
served. 
We will take it for granted that our speci- 
mens have safely passed through all perils by 
land and water, road and rail; that they have 
been quarried, boxed, carted over a roadless 
country to the nearest railway, and have with- 
stood 2,000 miles of jolting in a freight-car. 
The first step in reconstruction has been taken; 
the problem, now that the boxes are reposing 
on the work-room floor, is to make the blocks 
of stone give up the secrets they have guarded 
for ages, to free the bones from their envelop- 
ing matrix in order that they may tell us 
something of the life of the past. The method 
of doing this varies with the conditions under 
which the material has been gathered, and if 
from hard clay, chalk, or shale, the process, 
though tedious enough at best, is by no means 
so difficult as if the specimens are imbedded 
in solid rock. In this case the fragments 
from a given section of quarry must be as- 
sembled according to the plan which has been 
carefully made as the work of exhumation 
progressed, all pieces containing bone must be 
