10-4 PALAEONTOLOGY OP ILLINOIS. 



Sandalodus carbonarius, N. and W. 



PI. X, Fig. 4-5. 



Teeth sub-spatulate, one side being straight, the other regu- 

 larly rounded, broader end rounded to the straight margin, the 

 opposite extremity prolonged, narrowed, upper surface gently 

 arched longitudinally, laterally more strongly, highest point of 

 the arch forming an obtuse ridge nearer the straight than the 

 rounded margin; all the enamel coating very finely and evenly 

 punctate. 



All of the specimens included in the collection are imperfect, the narrower 

 end being broken. It is therefore impossible, as yet, to determine with accu- 

 racy the entire outline. We have therefore placed them in the genus Sanda 

 lodus, with some doubt, although, so far as shown, their characters ally them 

 more closely to the preceding species of Sandalodus than to any other fossil 

 teeth heretofore described. The general form seems to have been sub-spatulate, 

 considerably like that of S. spatulatus, though probably having the narrower 

 end less pointed. This portion of the tooth is much tbe thinnest, and has, 

 therefore, been liable to mutilation. The triturating surface is very finely and 

 beautifully pitted, the pits being deeper, more regularly spaced and more closely 

 set than in any of the teeth which have come under our observation. 



Figures 4 and 5 represent two specimens from the same locality. They differ 

 in size, though similar in form, except that one is dextral, the other sinistral. 



Formation and locality : Coal Measures, LaSalle, Illinois. 



Sandalodus l^evissimus, N. and W. 



PI. X, Figs. 6, 7, 8. 



Teeth of large size, sub-triangular in outline, terminating in 

 long and narrow pointed extremities, strongly arched in both 

 directions. Near the narrow end two faintly defined ridges are 

 discernable, rising from the longest margin and running ob- 

 liquely toward the centre of the tooth; entire upper surface 

 smooth and highly polished, but under the lens shown to be 

 very finely and uniformly punctate. 



