relations of each bone, the picture of the skeleton as it may have been when buried. The heavy ledges above are removed with pick and shovel, often with help of dynamite and a team and scraper. As he gets nearer to the stratum in which the bones lie the work must be more and more careful. A false blow with pick or chisel might destroy irreparably some important bony structure. Bit by bit he traces out the position and lay of the bones, working now mostly with awl and whisk-broom, uncovering the more massive portions, blocking out the delicate bones in the rock, soaking the exposed surfaces repeatedly with thin "gum" (mucilage) or shellac, channeling around and between the bones until they stand out on little pedestals above the quarry floor. Then, after the gum or shellac has dried thoroughly and hardened the soft parts, and the surfaces of bone exposed are further protected by pasting on a layer of tissue paper, it is ready for the "plaster jacket." This consists of strips of burlap dipped in plaster-of-paris and pasted over the surface of each block until top and sides, all but the pedestal on which it rests, are completely cased in, the strips being pressed and kneaded close to the surface of the block as they are laid on. When this jacket sets and dries the block is rigid and stiff enough to lift and turn over; the remains of the pedestal are trimmed off and the under surface is plastered like the rest. With large blocks it is often necessary to paste into the jacket, on upper or both sides, boards, scantling or sticks of wood to secure additional rigidity. For should the block "rack," or become shattered inside, even though no fragments were lost, the specimen would be more or less completely ruined. [Illustration: Fig. 41.--A Dinosaur skeleton, prospected and ready for encasing in plaster bandages and removal in blocks. (_Corythosaurus_, Red Deer River, Alberta.)] The next stage will be packing in boxes with straw, hay or other materials, hauling to the railway and shipment to New York. Arrived at the Museum, the boxes are unpacked, each block laid out on a table, the upper side of its plaster jacket softened with water and cut away, and the preparation of the bone begins. Always it is more or less cracked and broken up, but the fragments lie in their natural relations. Each piece must be lifted out, thoroughly cleaned from rock and dirt, and the fractured surfaces cemented together again. Parts of bones, especially the interior, are often rotted into dust while the harder outer surface is still preserved. The dust must be scraped out, the interior filled with a plaster cement, and the surface pieces re-set in position. Very often a steel rod is set into the plaster filling the interior of a bone, to secure additional strength.