38 PERMO-CARBONIFEROUS VERTEBRATES FROM NEW MEXICO. 



The material herein described, consisting mostly of a single skeleton (Cata- 

 logue No. 650 University of Chicago) of remarkable completeness, came from 

 another bone-bed, which for convenience is called the Miller Bone-bed, after its dis- 

 coverer, Mr. Paul C. Miller. This bone-bed is about half a mile east of the Baldwin 

 Bone-bed, and apparently in quite the same horizon. The skeleton, as fossilized, must 

 have been nearly or quite perfect. Perhaps a half or more of the tail, the distal half, 

 had been weathered out of the matrix and strewn on the surface below. Unfortu- 

 nately, before the skeleton, which lay about a foot above the chief bone-layer, was 

 recognized a stroke of the pick had mutilated the sacral region, which, with some of 

 the adjacent spines and the underlying left foot, was lost in the loose material thrown 

 over the dump. Although diligent search for these lost parts was later made, not 

 many of them were recovered. Dr. Williston has, regretfully, to add that he alone 

 is responsible for the mutilation. 



Upon the recognition of the skeleton lying in an orderly position, the speci- 

 men was carefully traced out and removed by Mr. Miller, with our aid, in a single 

 large block of matrix secured by bandages. The skeleton, as received in the 

 laboratory, was carefully cleaned of its investing matrix on the upper (right) side, 

 and then embedded in a plaster mold, after which it was turned over and worked 

 out from its better preserved lower (or left) side. As it lay in the matrix (pi. i, 

 fig. 2) it had what seemed to be a most remarkably natural position, with its 

 various parts all in articulation, or nearly so, as far as the pelvis. The right foot 

 and hand, falling on their inner sides, had their inner digits partly folded under 

 the others, but with little disturbance of their articulations. The shoulder-blade 

 of the upper side had slipped downward and forward a few inches. Apparently 

 after death, and before maceration had gone far, the cadaver had been gently 

 pushed cephalad and ventrad some 6 or 8 inches, dragging the under limbs dorsad 

 and caudad, bringing the left hand under the lumbar vertebrae and the left foot 

 under the pelvis. The curve of the dorsal vertebrse, as the skeleton lay, is per- 

 haps a trifle greater than was usual in life, and the skull evidently had suffered 

 more flexion than was commonly assumed in the living animal. These positions 

 and curves, however, have not been greatly modified in the mounted skeleton 

 (pi. I, fig. 3), the skull and vertebrae, for the most part, being still united by their 

 original matrix. 



Lying on the same level, and perhaps 2 or 3 feet distant from this skeleton, 

 there was aiiother (No. 652) skeleton of the same species, almost identical in size 

 and characters, the larger part of which had been washed out from its matrix and 

 strewn down the hillside, intermingled with the distal caudal vertebras of the more 

 complete skeleton. From the matrix of this second specimen the pelvis, posterior, 

 dorsal, and sacral vertebrae, the nearly complete left hind leg and a part of the 

 right one, and various other bones were recovered, parts which, fortunately, supple- 

 ment the more complete specimen almost perfectly. Furthermore, Ophiacodon 

 mirus seems to be well represented in the underlying bone layer by isolated bones, 

 many of which were collected, but have not yet been worked out. The skeleton, 

 therefore, as herein described, lacks some distal caudal vertebrae and the vertebral 

 spines of the posterior dorsal and sacral regions only. From all of which it results 

 that, aside from the intimate structure of the skull, there is perhaps no genus of 

 Permian vertebrates now more completely known than Ophiacodon, unless it be 

 Limnoscelis. 



The matrix of the Miller Bone-bed is a dark brown, indurated sandy clay, 

 weathering loose near the surface, but very hard, almost stony, farther in. It 

 was removed rather easily from the bones, leaving the original smooth surface. 



