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Show 356 so nearly resembles it that some consider the latter as only a variety of A. subtilita. Locality and position.- Katlahwoke Creek, just west of the second principal range of the Rocky Mountains: latitude 49° north, longitude 114° west; Carboniferous. CRETACEOUS SPECIES: LAMELLIBEANCHIATA. Genus NUCULA, Lamarck. NUCULA TBASKANA, Meek. . Nucula Tbaskana Meek ( 1857), Trans. Albany Inst., iv, 39. Shell trigonal- ovate, with both extremities rather narrowly rounded: cardinal border sloping from the beaks at an angle of about one hundred degrees; base forming a brpad gentle curve; beaks nearly centra], rather elevated; surface unknown; muscular impressions shallow; hinge having in each valve about fifteen teeth ou each side of the small pit for the reception of the ligament. Length, 0.27 inch; height, 0.18 inch; breadth, 0.16 inch. The only specimen of this species that I have seen is a cast, which is* o much worn as to show imperfectly the surface characters. As nearly as | can be determined, it appears to have been provided with rather distinct concentric lines of growth ; and, judging from a depression along the anterior slope of the cardinal margin, it was probably provided with a well- defined lunule. The species will probably be recogrfhsed by its ventricose trigonal- ovate form, and nearly central beaks. Since first describing this species, the only specimen in the collection has been mislaid, so that I am unable to give a figure of it. The specific name was given in honor of Dr. John B. Trask, of San Francisco. Locality and position.- The specimen came with others labeled i " Nanaimo, Vancouver's Island"; though it may have beeu collected at Komooks. Genus GRAMMATODON, Meek. GBAMMATODON ! VANCOUVEEBNSIS, Meek. Plate 3, figs. 5 and 5 a. Area Vancouver enm, Meek ( 1857), Trans. Albany Institute, iv, 40. Shell small, longitudinally oblong, moderately gibbous, comparatively thick and strong; anterior margin rounding up from b/ elow and meeting the end of the hinge nearly at right angles; posterior side somewhat obliquely truncated; base nearly straight and parallel with the hiDge; cardinal area rather narrow; hinge nearly or quite equaling the greater length of the shell; beaks located a little in advance of the middle, rather small, and incurved; posterior umbonal slopes prominently rounded from the beaks to the postero- basal margin; surface ora- J |