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- 



