stanton.] PHOLADID.E. 125 



"Length of largest specimen seen, 0.50 inch; height, 0.32 inch; con- 

 vexity, 0.25 inch." 



Prof. Meek noted the close resemblance of this species to certain 

 Laramie forms that are now regarded as belonging to Corbula subtri- 

 gonalis, and it may be that they are identical. It often happens that 

 very closely related forms of this genus are found at greatly separated 

 horizons, and for this reason, though a great many fossil species have 

 been named, they can seldom be used with any certainty in correlating 

 strata. 



Locality and position. — The types came from coal-bearing Cretaceous 

 beds near Cedar City, Utah, apparently equivalent with the lower part 

 of the Coalville section. The species is common beneath the main coal 

 bed at Coalville, Utah, and in the "third ridge" of the same section I 

 have collected specimens that seem to belong to it. 



Corbula kanabensis n; sp. 

 PI. xxvn, Figs. 5 and 6. 



Shell small, vcntricose, subequivalve, equilateral, transversely ovate 

 in outline; front end broadly rounded, forming a regular curve from 

 the beak to the base; posterior end abruptly contracted and angular; 

 beaks large, prominent, approximate; posterior umbonal slope sub- 

 carinate; basal margin usually thickened, and inflected so as to form 

 a flattened band. Surface bearing fine regular concentric lines. 



Length of a medium-sized specimen, 10 mm ; height, 7 mm ; convexity 

 of both valves united, 5 mm . 



Corbula traslci, from the Chico group of California as figured by 

 Gabb 1 and by Whiteaves, 2 is very much like this species, and direct 

 comparison of specimens may show that they are identical, but judg- 

 ing from the figures and description C. trasJci is more inequivalve 

 and less regularly convex, and it lacks the angular umbonal slope and 

 the thickening and deflection of the ventral border. 



Locality and position. — About 350 feet above the base of the Creta- 

 ceous section in Upper Kanab valley, southern Utah. 



PHOLADID^E. 



Genus PAEAPHOLAS Conrad. 



Parapholas sphenoideus White. 

 PI. xxvn, Figs. 1 and 2. 



Turnus sphenoideus White, 1876, Geol. Uinta Mts., p. 117. 



Parapholas sphenoideus White, 1879, Ann. Rept. U. S. Geol. Sur. for 1877, p. 300, PI. 5, 

 Figs. la-d. 



Eevised description : 



" Shell elongate, cuneate, inflated in front, narrowed and laterally 

 compressed behind; beaks anterior, incurved, adjacent; dorsal margins 



»Palaeont., California, vol. 1, PI. 22, Fig. 121. 'Mesozoic Foss., vol. 1, PI. 17, Fig. 3. 



