9 



lower tooth occup5-ing a position between and anterior to the 

 distal extremities of the mandible." 



These teeth he suggested were probably inserted in the 

 bone or cartilage between the tips of the mandibles. This 

 specimen in his opinion showed that, in one of the Placo- 

 derms at least, there was a dentition in advance or anterior 

 to what we had previously considered the distal extremities 

 of the dentary bones. 



Dr. Clark also showed a specimen of Dinichthys with a 

 tooth between the mandibles and also two larger teeth that 

 could occupy uo other position than between the mandibles 

 and ventured the prediction that when the dentition of these 

 Placoderms was fully understood, we should find a dentition 

 between and anterior to the mandibles. 



ON AN UNRECOGNIZED COAE-HORIZON IN 

 NORTHEASTERN OHIO. 



BY E. W. CLAYPOLE. 



In the third volume of the Geology of Ohio and in the 

 report of Stark County by Dr. J. S. Newberry, some con- 

 flicting accounts occur regarding the coal of the district. 



For example on page 165, Dr. N. writes: — " Some doubt 

 has been expressed among the inhabitants of Massillon 

 whether the coal that crops out at Bridgeport is identical 

 with that worked elsewhere in this vicinit3^ It is thinner 

 and lies somewhat higher than in most of the neighboring 

 mines. Still its physical character and composition as well 

 as its relation to the associated rocks seem to prove that it is 

 really Coal No. 1. A similar phase of the Massillon coal is 

 seen in the mine of the German Coal Company just north 

 of the stone quarry of Warthorst and Co. of Massillon. 

 Here also the coal is thin, very much laminated and even 

 somewhat slaty. This peculiarity of structure I have been 

 inclined to attribute to the fact that the coal seam in these 

 two mines is overlain by a great mass of sandstone which, 



