740 NORTH AMERICAN INDEX FOSSILS. 



Upper part of Knoxville near Paskenta, California. 



CXXVII. Melania Lamarck. (Compare Goniobasis.) 

 Turreted shells with surface varying from smooth to spirally 

 striate, ribbed or with sharp nodes upon the angulation of the 

 whorls. Aperture oval, rounded anteriorly. Operculum horny, 

 apex usually dehiscent. Form less slender and whorls more 

 strongly individualized than in Turritella. Jurassic-Recent. 

 449. M. insculpta Meek. (Fig. 1076, c.) Cretacic. 



FlG. 1076. a, Hypsipleura occidentalism enlarged; 6, H. gregaria ; c, Melania in- 

 sculpta ; d, e, M. wyomingensis ; f, M. sculptilis ; g, M. taylori ; h, i, Melanopsis 

 americana. (a, b, after Stanton, the others after White, U. S. G. S., III.) 



Sutures scarcely impressed, ribs continuous on the flattened 

 whorls, thick, round and separated by impressed lines only. 

 Laramie of Wyoming. 



450. M. (Pachychilus) wyomingensis. (Fig. 1076, d } e.) 



Cretacic. 



Young like the adult of the preceding species ; later whorls ab- 

 ruptly angulated, with concave shoulders, and the ribs replaced 

 by spinose nodes on the angulation. Spirals simple, not strong. 



Laramie of Wyoming and Colorado. 



451. M. sculptilis Meek. (Fig. 1076,/.) Miocenic. 

 Short, with comparatively few whorls. Sutures with a false 



