298 TRANSACTIONS OF THE [xMAR. 15, 



trary, as appears on p. 181 (op. cit.), the union is made upon no 

 better ground than a suspicion. 



In regard to the union of Sandalodus grandis^ N. & W., with 

 Gochliodus ? crassiis, N. & W., Psammodus ? semicylindr'icus^lS . 

 & W., and P. ? rhomboideus, K. & W., they say, " these names 

 were applied to abnormally worn and otherwise imperfect ex- 

 amples of the maxillary posterior form (tooth?) of this species." 

 This statement I am quite unable to accept. That such a tooth 

 as that represented by figure 9, Plate X., Vol. II., Geological 

 Survey of Illinois, could ever be worn or distorted into such 

 forms as figures 4, 5 and 6 of Plate XI. (op. cit.') seems to me 

 quite impossible. The teeth represented by the latter figures 

 were placed in Psammodus only pi'ovisionally and with a query. 

 I shall be very glad when, in the light of new material, they 

 may be referred to their proper genera, but I cannot say that 

 I think it has yet been done. 



Deltodus inornatus, n. sp. 

 PI. XXIII., figs. 10-11. 



Maxillary posterior tooth long-triangular in outline, four 

 inches long by one and a-half inches wide, strongly twisted, 

 surface smooth, without angles or traversed folds ; posterior 

 margin rounded ; mandibular posterior tooth similar to that of 

 the upper jaw in general character, but shorter and broader, two 

 and three-quarter inches in length, by one and three-quarter 

 inches wide. The tooth is thick and ponderous, its surfaces 

 plain, its angles rounded. 



These teeth are nearly of the size and form of those of Deltodus 

 grandis N. & W., but are distinguishable at a glance b}^ their 

 smooth surfaces and rounded outlines ; the crown enamel is 

 punctate as usual, but there are no longitudinal or transverse 

 bands or ridges and the whole aspect is exceedingly modest and 

 plain. 



Formation and locality, Kinderhook group, Le Grande, Iowa. 

 Type in the collection of William F. E. Gurley, Danville, 111. 



Deltodus complanatus, N. & W. 

 PI. XXIV., figs. 1-7. 



In Vol. II. of the Illinois Geological Survey, p. 98, PI. IX.> 

 fig. 4 is published a description of a tooth to which this name 

 was given. It was somewhat imperfect and had been crushed 

 and flattened. This was from the Burlington limestone, and in 

 the same volume (p. 112, PI. XI., figs. 8-9) were described and 



