GEOLOGY AND PALÆONTOLOGY. MAMMALIA OF THE Lower EOCENE BEDS.-As stated in my report to Lieut. Wheeler in 1877, no vertebrate remains have been found in the Puerco beds, which underly the Wasatch in New Mex-. ico, up to the present time. It was therefore uncertain whether they form the top of the Cretaceous or the bottom of the Tertiary series. I have recently obtained evidence of the existence of Mammalia and turtles in them, so that their position is probably in the Tertiary division, as already suspected by Dr. Endlich and myself. Two species of flesh-eaters recently received from beds that may prove to belong to the Puerco group, do not belong to genera hitherto known from the Wasatch. The one which I first describe is of considerable interest as representing a very primitive type of carnivorous dentition. Periptychus carinidens, gen. et. sp. nov. Creodontium. Char. Gen. No distinct sectorial teeth, the first and second true inferior molars similar. They support a principal median cusp, a broad heel and a prominent anterior cingulum. The heel is more or less divided into tubercles; the anterior cingulum is on the inner side, and represents the anterior cusp of a sectorial tooth. On the inner side of the principal cusp a cingulum rises, forming a flat internal tubercle. Last molar not smaller than the others; premolars unknown. This genus belongs to the Amblyctonida with Amblyctonus and Palæonyctis. It differs from both in the rudimental character of the anterior cusp, and from the former, in the presence of the internal tubercle. In Mesonyxr the heel has a median cutting edge. Char. Specif. Parts of both mandibular rami and the shaft of a humerus represent this species. They indicate an animal of the size of the red fox, but much more robust. The mandibular ramus is rather shallow and thick, and the molars are not large. The heel of the penultimate supports three tubercles, of which the external is the largest. The anterior cingulum supports a small cusp, and then rises to the internal tubercle, which is compressed. The sides of all the cusps are marked with distinct, well separated, vertical ridges. Each extremity of the internal cusp is connected with the principal cusp by a ridge. The first true molar has fewer cusps. Those of the heel are scarcely distinct, and form a border which rises prominently into the flat internal tubercle, which forms a narrow longitudinal blade. The anterior cingulum has no cusp and does not rise into the inner tubercle. The principal cusp has a strong entering groove next the inner tubercle. Length of crown first molar, .0115; width of do., .006; elevation of do., .006. Length of second molar, .011; width of do., .007; elevation of do, .0065. Depth of ramus at do., .020. The species is a good deal smaller than the Amblyctonus sinosus. Deltatherium fundaminis, gen. et sp. nov. Char. Gen. Fam. Leptictida, agreeing with Ictops and Mesodectes in possessing an internal tubercle of the third superior premolar, but differing from both in having but one external cusp of the fourth superior premolar. Char. Specif. Represented by the dentition of both maxillary bones minus the canines. The second premolar is convex on the inner face. The base of the third is a nearly equilateral triangle. The bases of the true molars are triangles, with the bases external. The internal angle supports an acute cusp, and has a posterior basal cingulum, which is very strong in the last three molars. The two external cusps of the first and second molars are situated well within the base, which is folded into a strong cingulum. This cingulum develops strong anterior and posterior angles. This is the largest species of the family yet discovered. Extent of series of last six molars, m. .045; of true molars, .026; diameters of fourth premolar, anteroposterior, .0074; transverse, .0076; do. of second true molar, anteroposterior, .0087; transverse, .0100. This species was a fourth larger than the common opossum, and very much resembles it in dental characters. -E. D. Cope. THE FAULT OF THE YANKEE HILL SILVER DEPOSIT OF LEADVILLE, COLORADO.-The formation on the surface of Fryer Hill and adjoining hills east of Leadville, Colorado, consists of an uncommonly deep "wash," of boulders embedded in earth, varying from 150 to 175 feet in depth. Immediately under this wash we encounter a dark gray eruptive or porphyritic granite. This porphyritic granite varies from twenty feet, in the Denver City discovery shaft, on the west, to nearly if not quite four hundred feet in thickness in some of the claims adjoining the property to the east; and the dip is quite uniformly north north-east, although at the Denver City discovery shaft, a local wave causes the ore body to dip slightly to the west. Under this gray porphyritic granite a low grade deposit has invariably been encountered by all of the shafts which have so far penetrated through it, which consists principally of a clayey mass varying from five to twenty feet in thickness, with small bodies and stringers of low grade silver ore interspersed through it. So far I have not learned of any ore being found in this deposit which has assayed over five to forty ounces, although it has been penetrated at nearly a dozen different points in this section, viz: in the Denver City discovery shaft, in the Shamus O'Brien, in the Little Miami, the El Paso, the Tip Top, the Little Sliver, the Compromise and other shafts which I will not occupy space in enumerating. To the west of a line drawn through the Little Sliver and Denver City discovery shafts the main contact comes so much nearer the surface that these overlying formations have undoubtedly been scored off by glacial action. This is plainly evident at points in the Lee, the Little Pittsburgh and the New Discovery claims, where the excoriation has cut down clear through the white porphyry and iron and left the boulder wash lying upon the silver-bearing iron itself. Under the low grade ore bed just described, comes in a soft, white feldspathic porphyry, which in this vicinity usually averages about fifty feet thick, although I know of a point about one mile east, where it was found to be over two hundred feet thick. This white porphyry lies immediately above the iron with which and in which the ore bodies are found. A study of the accompanying diagrams will aid in gaining a clear idea of the lay of the different formations. Enough development has already been accomplished at numerous points to prove that the ore body uncovered in the Denver City discovery shaft belongs to the Fryer hill deposit, and it is equally certain that such ore deposit with a few local waves, and also possible slight faults, continues in a practically unbroken dip from the extreme western workings of the Chrysolite group, in an easterly direction for a distance of over four thousand feet, to the well defined geological break or fault (of at least four hundred feet slip) which gives rise to what is commonly known as the "Yankee Hill Contact." This break corresponds very nearly to the fault which separates Carbonate hill from Iron hill, and which fault is better understood, as the foot wall of the ore bodies on those hills is a heavy ledge of limestone undoubtedly in place; whereas the foot wall of the present Fryer hill bodies is generally a layer of true quartzite, or metamorphosed sandstone, which in turn lies upon a hard white, silicious porphyry, similar to that which overlies the whole of the Carbonate and Iron hill ore bodies. In places this quartzite is wanting, in which case the mineral lies upon the hard white porphyry. This porphyry has not yet been passed through by any of the shafts so far sunk upon Fryer hill, and what underlies it is still an unsolved problem. I will venture to predict, however, that other and possibly larger ore bodies than those now being worked are yet to be found in place, with lime as a foot wall, under this porphyry; and such bodies will probably also be richer in lead, if not in silver, as is the case with the ore bodies found on lime in other portions of the camp. This, at least, is a matter which should be proved by sinking one or more shafts on Fryer hill to the granite bed rock.-W. G. Shedd. FILHOL ON PROÆLURUS.-Mr. H. Filhol has recently published a monograph on this genus in the Society of Physical and Natural Sciences of Toulouse, illustrated by five plates. Proalurus was discovered by Mr. Filhol, and the remains of three species occur in the upper Eocene of Quercy, and the lower Miocene of St. Gerand le Puy. The discovery, at the latter locality, of a nearly perfect skeleton of the P. lemanensis, gave rise to the present memoir. Mr. Filhol shows that in this genus, the foramina of the base of the skull characterístic of the Nimravide and Cryptoproctidæ, are all present. These are the two alisphenoids, the postglenoid, and the distinct carotid and condyloid. These foramina were all assigned to Proælurus by inference, prior to their discovery, in the article on the extinct cats of America in the December, 1880, number of the NATURALIST, and the genus was therefore referred to the Nimravida. Mr. Filhol, however, shows that there are five toes on all the feet instead of five and four, so that Proælurus must be referred to the Cryptoproctida. A detailed comparison gives the resemblances and differences between the P. lemanensis, and the C. ferox. In this memoir we have another interesting contribution to the history of the types of the Eocene fauna whose representatives yet remain in the southern hemisphere. THE CLASSIFICATION OF THE PERISSODACTYLA. -In the forthcoming Report of the U. S. Geological Survey of the Territories of Dr. Hayden, the following arrangement is given by Professor Cope. I. Anterior exterior crescent of superior molars shortened and connected with an anterior basal lobe; inferior molars with cross-crests; premolars different from molars. 1. Toes 4-3.. 2. Toes 3-3... . . .Lophiodontida. II. Anterior exterior crescent of superior molars like div. I; inferior molars with cross-crests; superior molars and premolars alike, with cross-crests. 3. Mastoid bone forming part of the external wall of the skull; no postcotyloid tuberosity of the mandible; neck elongate.... Hyracodontida. 4. Mastoid bone excluded from the walls of the skull by the contact of the occipital and squamosal; a postcotyloid tuberosity of the mandible; neck short.... .... Rhinocerontida. III. Exterior crescentoid crests of superior molars subequal; inferior molars with cross-crests. 5. Superior molars and premolars alike and with cross-crests........Tapirida. IV. The external crescentoid crests of the superior molars subequal; inferior molars with crescents. A. Premolars different from molars; the superior with only one internal cusp. 6. Toes 4-3 · ... Chalicotheriida. AA. Premolars like molars, with two internal lobes above. 7. Toes with digits 4-3. 8. Toes with digits 3-3 9. Toes with digits I—I. Palæotheriida. ...Equida, GEOLOGICAL NEWS.-Professor Huxley evidently believes in American palæontology. He is still lecturing on our fossil horses, concerning which he apparently has information not generally accessible to American palæontologists. He has expressed the opinion that the primitive mammalia were five-toed, after it had been announced in this country, and he has recently discovered that the Insectivora represent a primitive type of mammalia. This view was proposed here six years ago, long enough ago for Professor Huxley to have forgotten where the idea originated.-Professor Wilder in Science, suggests that the large sacral neural cavity found by Marsh in Hypsirhophus (Stegosaurus), was not filled by nervous matter. This view has doubtless occurred to most per |