"The skeleton or hard parts of these very remarkable animals had been known for over forty years, and a few specimens of the epidermal covering, but it was not until the discovery of the Sternberg specimen that a complete knowledge of the outer covering of these dinosaurs was gained. It appears probable that in a number of cases these priceless skin impressions were mostly destroyed in removing the fossil specimens from their surroundings because the explorers were not expecting to find anything of the kind. Altogether seven specimens have been discovered in which these delicate skin impressions were partly preserved, but the 'Trachodon mummy' far surpasses all the others, as it yields a nearly complete picture of the outer covering. "The reason the Sternberg specimen (_Trachodon annectens_) may be known as a dinosaur 'mummy' is that in all the parts of the animal which are preserved (_i.e._ all except the hind limbs and the tail), the epidermis is shrunken around the limbs, tightly drawn along the bony surfaces, and contracted like a great curtain below the chest area. This condition of the epidermis suggests the following theory of the deposition and preservation of this wonderful specimen, namely: that after dying a natural death the animal was not attacked or preyed upon by its enemies, and the body lay exposed to the sun entirely undisturbed for a long time, perhaps upon a broad sand flat of a stream in the low-water stage; the muscles and viscera thus became completely dehydrated, or desiccated by the action of the sun, the epidermis shrank around the limbs, was tightly drawn down along all the bony surfaces, and became hardened and leathery, on the abdominal surfaces the epidermis was certainly drawn within the body cavity, while it was thrown into creases and folds along the sides of the body owing to the shrinkage of the tissues within. At the termination of a possible low-water season during which these processes of desiccation took place, the 'mummy' may have been caught in a sudden flood, carried down the stream and rapidly buried in a bed of fine river sand intermingled with sufficient elements of clay to take a perfect cast or mold of all the epidermal markings before any of the epidermal tissues had time to soften under the solvent action of the water. In this way the markings were indicated with absolute distinctness, ... the visitor will be able by the use of the hand glass to study even the finer details of the pattern, although of course there is no trace either of the epidermis itself, which has entirely disappeared, or of the pigmentation or coloring, if such existed.