the same sandstone, in the quarry at Cummingstone, near Elgin, a continuous series of thirty-four impressions have been observed. The impressions are in pairs, forming two parallel rows, the hind one being one inch in diameter.
had some years before determined the true saurian nature of the impression of the skeleton of the trunk and part of the head of a small reptile discovered by Mr. Patrick Duff of Elgin, at Spynie, and noticed by him in the " Elgin Courant " of October 10th, 1851, as evidence of an air-breathing vertebrat in " Old Red Sandstone." The specimen was submitted by Mr. Duff to my examination, the result of which was given, Dec. 15, 1851, in the "Literary Gazette" of that week, as follows : " It is the impression, in two pieces, of a grey variety of the old red sandstone, of a long and slender four-footed vertebrate animal, four inches and a half in length, clearly belonging, by the form, proportions, and positions of the scapular and pelvic arches, and their appended limbs, to the reptilian class. The osseous substance has disappeared ; the cavities in the sandstone which contained it remain, stained by a deposit of an ochreous tint. The impressions are so well defined, as clearly to show that there were twenty-six vertebrae between the skull and sacrum, two sacral vertebrae, and thirteen caudal vertebrae, before the tail disappears by dipping into an unexposed part of the matrix. Impressions of twenty-one pairs of ribs are preserved, all very slender, short where they commence near the head, but rapidly gaining length as they are placed further back. The cervical and anterior ribs are expanded, but not bifurcate, at their vertebral end ; all the ribs articulate close to the bodies of the vertebrte. In the crocodilian reptiles the anterior ribs are bifurcate, and the posterior ones, with a simple head, articulate with long diapophyses. The distinctive characters of the batrachian skeleton are the double occipital condyle ; ribs wanting, or very short and subequal ; a single sacral vertebra, and rib shaped ilium. The first character cannot be determined, the
occipital articulation not being preserved in the fossil. Instead of the second character, the fossil shows ribs of varied length, and most of them much longer than in the salamanders, newts, or any known Batrachian. With regard to the third character, the impression in the matrix clearly shows two sacral vertebrae and a short subquadrate pelvis.
" Both the humerus and the femur show the lacertian sigmoid shape, and near equality of length, which distinguish them alike from the crocodilian and batrachian orders ; they are likewise, as in lizards, relatively longer than in the newts and salamanders. Near the imperfect impression of the head may be seen the hollow bases of some large, slightly-compressed, conical teeth, which also tell for the saurian and against the batrachian nature of this ancient reptile. I propose to call it Leptopleuron laccrtinum.* Many particulars of minor import, bearing upon the more immediate affinities of this most rare and interesting fossil, have been noted, and will be given, with the figures, in my History of British Fossil Reptiles, for which work Mr. Duff has kindly consented to place the specimen at my disposal. In the meanwhile, I beg to offer the above précis of the main characters of the fossil.—RICHARD OWEN." Other palaeontologists regarded the fossil as a batrachian reptile ; but no evidence, osteological or dental, has been pointed out in support of this view.* With regard to the geological age of the calcareous sand stone containing Staganolepis and Leptopleuron, the author has remarked, in the article " Palaeontology," when the belief of some eminent geologists in the Devonian age of the stratum is quoted—" As yet, however, no characteristic Devonian or Old Red' fossils of any class have been discovered associated with the foregoing evidences of reptiles, which, according to the determination of strata by characteristic fossils, would belong to the secondary or mezozoic period."t It is, most probably, of triassic age.