110 IOWA GEOLOGICAL SURVEY 



Cladodus formosus Hay. 



1903. Cladodus formosus O. P. Hay, Arner. Geol. 30, p. 373, text-fig. 1. 



A small species resembling C. concinnus from the Huron shale 

 of Ohio in general form, but the principal cone more robust, 

 with rather strongly convex anterior face, the basal portion of 

 which becomes somewhat flattened and at last indented. The 

 anterior face is also more conspicuously striated than in the 

 Ohio form, there being about twenty sharp carinations near the 

 base, and half that number toward the apex. There are two pairs 

 of divergent, striated lateral denticles, of which the internally 

 situated one is the larger. Total height about 1.1 cm; length of 

 base 1.5 cm. 



Formation and locality. Ouray limestone (Upper Devonian) ; 

 south slope of Needle Mountains, in Needles Mountain Quad- 

 rangle, Colorado.* 



Cladodus urbs-ludovici, sp. nov. 



(Plate III, Fig. 3) 



A moderate-sized species, in which the teeth are composed of 

 a robust and erect median cone without lateral denticles, sup- 

 ported by a- small narrow base with gradually sloping lateral 

 alae. Principal cone with gently convex faces and laterally 

 compressed edges toward the apex, which is acute. Anterior 

 face ornamented with numerous slightly wavy longitudinal 

 striae, of which about twenty are to be counted toward the base ; 

 striae of posterior face not extending to the apex, which is 

 smooth on that side. Total height of tooth in holotype, 1.6 cm ; 

 length of base 1.8 cm. 



This species is founded upon a unique tooth of which the apical 

 portion is preserved intact, but the basal portion of the crown is 

 seen in impression and the root in cross-section, owing to frac- 

 ture and subsequent weathering. Numerous Conodont teeth 

 are associated with the specimen in the containing matrix. In 



* The horizon immediately overlies the fish-bearing strata of the Elbert for- 

 mation, described by Dr. Whitman Cross in the American Journal of Science for 

 October, 1904. The upper part of the Ouray limesi-one carries a Mississippian in- 

 vertebrate fauna, which has been described bv Dr. G. H. Girty in Professional 

 Paper No. 16 of the U. S. Geol. Survey, 1903. 



