NATURAL SCIENCES OF PHILADELPHIA. 19 



February G. 



The President, Dr. Ruschenberger, in the chair. 



Twenty-five members present. 



The following paper was presented for publication: "Synopsis 

 of the Species of Chelydrinse." By E. D. Cope. 



Notice of Corundum. Prof. Leidy remarked that the speci- 

 mens of corundum presented this evening were of unusual interest 

 and beauty. They were from Franklin, Macon County, N. C, 

 where the mineral is said to occur in some abundance, contained 

 in a vein of chlorite. The specimens are fragments of large 

 crystals, presenting portions of the faces of the latter. They 

 exhibit in association the three varieties of the mineral. Mainly 

 composed of gray corundum, with the crystal surfaces of bright 

 ruby, and the interior with mingled rich blue sapphire. The ruby 

 and sapphire, though of line color, have not been found in a con- 

 dition fit for gems. Some small crystals of gray corundum 

 exhibit brilliant and translucent summits of ruby. 



A large crystal of corundum from the same locality is now in 

 the cit} r . It is a truncated, six-sided, compressed pyramid, about 

 two feet in length, and weighs about three hundred pounds. The 

 summit is one foot by six inches in diameter. It is much fissured, 

 and has a quantity of chlorite adherent or partially imbedded 

 towards the base. The surface is ruby; the interior is of gray 

 corundum with mingled sapphire. 



Remarks on Fossils from Wyoming. Prof. Leidy made the 

 following observations: The various fossils from the tertiary for- 

 mation 'jf Wyoming, which both I and Prof. Marsh have referred 

 to Lophiodon, I suspect to belong to a genus distinct from this, as 

 represented by the species Lophiodon isselense, of France. In 

 this, as in the related and living Tapir, there are six molars in 

 both upper and lower series. In the upper premolars of the Lo- 

 phiodon isselense a single ridge extends from the outer part of the 

 crown to the inner lobe, and the last lower molar has a trilobate 

 crown. 



In Hyrachyus agrarius, which I suspect to be the same as the 

 Lophiodon Bairdianus of Prof. Marsh, there are seven molars to 

 both upper and lower series. The upper two back premolars have 

 two well-marked ridges extending between the outer and inner 

 part of the crown; and the last lower molar has a bilobed crown, 

 as in the Tapir. 



Portions of two lower jaws, which I exhibit, probably belong 

 to a smaller species of Hyrachyus, perhaps to the same animal as 

 18Y2.] 



