496 PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [Julie 13, 



by Mr. Moore, and above described, agree in size with that of the 

 little mammal indicated by the unequivocally mammalian teeth. 

 Nevertheless the depth and form of the terminal articular cups in 

 those vertebras, the sharpness of their margin and smoothness of 

 their surface, accord very closely with the Reptilian structure, and 

 hitherto have only been met with in cold-blooded Vertebrates. 



Moreover, unquestionable parts of small Saurians and Fishes are 

 mingled with the Microlesies teeth in this ossiferous deposit, and, 

 indeed, predominate there. 



In fact, in the last set of specimens which I received a few days 

 ago from Mr. Moore, seven, more or less perfect, are of the partially 

 ossified vertebras of a small cartilaginous fish. The following is the 

 result of the examination of these seven specimens : — 



They are rings or short cylinders of bone, with a circular area 

 having a diameter about four times the length of the cylinder, that 

 length being from four to six times the thickness of the cylinder- wall. 



This wall is of unequal length — one side, in some, being twice that 

 of the opposite side. The first specimen shows two parallel rough 

 surfaces, for the articulation of processes or lamella?, either bony or 

 gristly, bounding a probably neural canal. The cavity of the cylinder 

 in this specimen is blocked up by matrix. 



A second specimen, with the area empty, shows, besides the (neura- 

 pophysial ?) surfaces on the broader part of the ring, an opposite 

 pair of narrower, parallel (hsemapophysial ?) tracts on the narrower 

 part of the ring. 



A third specimen shows part of the apophysis adhering to one 

 of the parallel surfaces on the broader part of the cylinder, and ex- 

 tending outward as well as upward (or downward), indicating that it 

 has bounded the side of a canal with a diameter wider than that of 

 the centrum. 



One of the broken specimens (a half- cylinder) includes the 

 broader half, with the parallel longitudinal tracts on the outer sur- 

 face, to one of which adheres the base of an apophysis extending 

 outward. 



The fifth is an entire ring, and shows the parallel longitudinal 

 apophysial tracts on the two opposite (broader and narrower) parts 

 of the cylinder, which is, however, a little broader where it supports 

 the surfaces on the narrower side than at the proximity of that part. 



Another entire ring has a more uniform length, or breadth, of wall 

 than the others, and shows a small single apophysial surface at op- 

 posite sides the of ring. 



The seventh specimen (a fragment) shows the ring to be a very 

 little thicker at its ends than at its middle ; and, like the others, it 

 is quite smooth on the flattened inner surface. 



There is no character of a cervical or other vertebra of a Mamma- 

 lian animal in any of these specimens. "Were it not for the apo- 

 physes or apophysial surfaces, they might pass for the bony rings of 

 a windpipe, as in Birds and some Rodents. But they more closely 

 resemble the ossified vertebral cylinders in Heptanchus and Chimcera, 

 in which the neur- and hseru-apophyses are so far ossified as to 



