After this preparation is completed, each part being soaked repeatedly
with shellac until it will absorb no more, the bones can be handled
and laid out for study or exhibition. Then, if they are to be mounted
for a fossil skeleton, comes the work of restoring the missing parts.
For this a plaster composition is used.
Where only parts of one side are missing the corresponding parts of
the other side are used for model; where both sides are missing, other
individuals or nearly related species may serve as a guide. But it is
seldom wise to attempt restoration of a skeleton unless at least
two-thirds of it is present; composite skeletons made up of the
remains of several or many individuals, have been attempted, but they
are dangerous experiments in animals so imperfectly known as are most
of the dinosaurs. There is too much risk of including bones that
pertain to other species or genera, and of introducing thereby into
the restoration a more or less erroneous concept of the animal which
it represents. The same criticism applies to an overly large amount of
plaster restoration.
[Illustration: Fig. 42.--Bone-Cabin Draw on Little Medicine River
north of Medicine Bow, Wyoming. The location of the quarry is
indicated by the stack of crated specimens on the left, and close
to it the low sod-covered shack where the collecting party lived.
Beyond the draw lies the flat rolling surface of the Laramie
Plains and on the southern horizon the Medicine Bow Range with Elk
Mountain at the center.
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