304 NORTH AMERICAN INDEX FOSSILS. 



300. T. ? humboldtensis Gabb. Triassic. 



Of medium size. Front truncate and marked by a simple or 



double fold and sinus. Pedicle valve slightly flattened across the 



middle. Beak broad, prominent, but slightly incurved and trun- 



Fig. 379. Terebratula harlani. Example of average size. (After Whitfield.) 



cated by a large foramen. Cardinal borders strongly inflected and 

 flattened, forming an angularity along the edge of the beak. Sur- 

 face smooth except for strong and irregular concentric growth 

 lines. 



Triassic of Nevada and Nicola Lake, Canada. 



301. T. harlani Morton. (Figs. 379 and 380.) Cretacic-Eocenic. 



Large (sometimes 2^ inches long), elon- 

 gate- ovai with subparallel sides. Front 

 more or less truncate, at times slightly bilo- 

 bate. Valves very ventricose, covered with 

 concentric growth lines. Pedicle valve with 

 large beak, strongly incurved ; foramen 

 Fig. 380. Terebratula large. Shell substance finely punctate. 

 harlani. Interior showing „ Cretacic (Rancocas) of New Jer- 



loop. I After Whitfield.) *T . „ \, . _ ' t? • 



Y sey, Delaware, South Carolina. Locenic 



of Maryland. 



XCIII. Terebratulina d'Orbigny. 



Ovate, biconvex. Cardinal extremities faintly auriculate. Ped- 

 icle valve with circular foramen ; deltidial plates small, generally 



