358 CRETACEOUS PALEONTOLOGY. 



1868. Terebratula Harlani Cook, Geol. N. J., p. 375, two figs. 

 1868. Terebratula Harlani Con., Cook's Geol. N. J., p. 723. 

 1870. Terebratula Harlani Credner, Zeitsch. d. Deutsch. Geol. 



Gesell., vol. 22, p. 221. 

 1886. Terebratula Harlani Whitf., Pal. N. J., vol. i (Monog, 



U. S. G. S., vol 9), p. 6, pi. i, figs. 15-23. 



1891. Terebratula gorbyi Miller, Adv. Sheets I7th Rep. Geol. 



Surv. Ind., p. 77, pi. 13, figs. 3-4. 



1892. Terebratula gorbyi Miller, i7th Ann. Rep. Dept. GeoL 



and Nat. Res. Indiana, p. 687, pi. 13, figs. 3-4. 

 1898. Terebratula harlani Bagg, Am. Geol., vol. 22, p. 370. 

 1901. Terebratula harlani C. and M., Md. Geol. Surv., Eocene, 



p. 204, pi. 58, figs. 2-3. 

 1905. Terebratula harlani Johns., Proc. Acad. Nat. Sci. Phil. r 



1905, p. 6. 



Description. Shell large, the dimensions of a large individual 

 being : length, 59 mm. ; width, 36 mm. ; thickness, 36 mm. ; elon- 

 gate oval in outline with subparallel sides, often becoming more or 

 less cylindrical in old specimens; the front margin more or less 

 truncated, sometimes bilobate from a flattening or lobing of the 

 valves anteriorly. Pedicle valve very ventricose, becoming almost 

 gibbous in old individuals, the beak large, strong, incurved, trun- 

 cated at the apex by the large foramen whose diameter is greater 

 externally than within, the truncation in full-grown shells being 

 parallel with the axis of the valves ; lateral margins of the beak 

 subangular; the median portion of the valve often flattened or 

 .somewhat concave toward the front and the lateral slopes some- 

 times impressed. Brachial valve much less convex than the pedi- 

 cle, the beak small and strongly incurved; the median portion of 

 this valve flattened or concave anteriorly, the flattened portion 

 being bounded on each side by a more or less distinct angular ridge 

 which separates it from the lateral slope, this feature often being 

 exaggerated to so great an extent as to give the anterior half of 

 the shell a decidedly plicate appearance ; internally the crura are 

 slender near their junction with the valve, and expand rapidly 

 to form a broad loop from 8 mm. to 15 mm. in length, with the 



