118 ANIMALS OF THE PAST 
stuck together, and weak parts strengthened 
with gum or glue. Now the mass is attacked 
with hammer and chisel, and the surrounding 
matrix slowly and carefully cut away until the 
contained bone is revealed, a process much 
simpler and more expeditious in the telling 
than in the actuality ; for the preparator may 
not use the heavy tools of the ordinary stone- 
cutter: sometimes an awl, or even a glover’s 
needle, must suffice him, and the chips cut off 
are so small and such care must be taken not 
to injure the bone that the work is really te- 
dious. This may, perhaps, be better appreci- 
ated by saying that to clean a single vertebra 
of such a huge Dinosaur as Diplodocus may 
require a month of continuous labor, and that 
a score of these big and complicated bones, 
besides others of simpler structure, are in- 
cluded in the backbone. The finished speci- 
men weighs over 120 pounds, while as orig- 
inally collected, with all the adherent rock, the 
weight was twice or thrice as great. Such a 
mass as this is comparatively small, and some- 
times huge blocks are taken containing entire 
skulls or a number of bones, and not infre- 
