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.] In some instances the missing parts of a skeleton are not restored, because, even though but a small part be gone, we have no good evidence to guide in its reconstruction. This gives an imperfect and sometimes misleading concept of what the whole skeleton was like, but it is better than restoring it erroneously. Usually with the more imperfect skeletons, a skull, a limb or some other characteristic parts may be placed on exhibition but the remainder of the specimen is stored in the study collections. [Illustration: Fig. 43.--American Museum party at Bone-Cabin Quarry, 1899. Seated, left to right Walter Granger, Professor H.F. Osborn, Dr. W.D. Matthew; standing, F. Schneider, Prof. R.S. Lull, Albert Thomson, Peter Kaison.]