BUFFALO SOCIETY OF NATURAL SCIENCES 55 



to one of us (Hussakof) for study, through the kindness of Director 

 John M. Clarke. Among them was one especially noteworthy — the 

 left margin of a cranium about as large as that of D. curtus, or of a 

 size to go with the present mandible. No doubt complete plates 

 of this species will some day be found. 



The mandible is too large to belong to D. tuberctdaius Newberry, 

 which is known only by a small antero-dorsolateral, ornamented with- 

 rather large, stellate tubercles.^' 



Regarding the locality and horizon at which the mandible was 

 found, Mr. Armstrong has kindly supplied the following note : 



' 'The locality is on the east branch of Twelve Mile Creek, in Green- 

 field Township, Erie County, Pa., 200 yards south of the township 

 Hne. The layer from which it came is approximately 100 feet above 

 the base of the Chemung. The shells on the slab are principally 

 Productella lacrymosa, very poorly preserved. Spirifer disjunctus, 

 Camarotoechia contracta, and Leiorhynchus newberryi are also present in 

 this layer. All four species are plentiful both above and below this 

 horizon — above, as far up as the strata are exposed; below, as far as 

 the base of the Chemung. There are of course many other species, 

 but they are not so persistent." 



Dinichthys tenuidens, n. sp. 



(PI. 69, fig. 2) 



E 2596 Type. — A small left mandible, in matrix, shown in outer 

 view. Length, 67 mm.; depth, at end of functional 

 portion, 10. 



Formation and Locality. — Rhinestreet shale; Cazenovia Creek, near 

 WiUink, N. Y. 



Mandible of small size, the fimctional portion more slender, i.e., not 

 so deep, as the blade, or inserted portion. Fimctional margin occupy- 

 ing more than half the length of the element; with a slender, pointed 

 beak anteriorly, and a second cusp, also large and pointed, about f 

 the length of the cutting margin behind it; part of cutting margin 

 between the two beaks, a sharp, almost straight cutting edge, and this 

 portion of mandible more slender than part back of second cusp. 



[Tenuidens, in allusion to the slender character of the mandible.] 



21 Newberry, J. S.: Paleoz. Fishes N. Amer., 98, pi. xxxii, fig. 3, iS 



