Spondylus rugosus Packard, 1922
PACKARD, E. L. 1922. New species from the Cretaceous of the Santa Ana Mountains, California. University of California Publications, Bulletin of the Department of Geological Sciences, 13 (10): 413-462, pls. 24-38. [p. 421, pl. 27, fig. 3; pl. 30, fig. 3; pl. 31, fig. 3]
1922 Spondylus rugosus Packard, 1922
E. L. Packard, 1922, plates 27, 30, 31.
|
«Type specimen 12277, ColI. Invert. Palae.; specimen 12322, ColI. Invert. Palae., Univ. Calif., loc. 2143.
Shell medium size, very inequilateral, inequivalve; right valve rather flat; left valve ventricose and very rugose. Outline of left valve irregular due to its nodose character. Umbone of left valve very tumid and irregular; umbone of right valve small. Ear long, equaling about one-third the height of the shell. Left valve ornamented by rough growth lines which are in places extended into irregular, lamellar processes, giving a very rough aspect to that valve. Right valve ornamented by numerous fine radiating ribs with imbricated spaces and interspaces. Hinge and pallial line unknown. Ventral margin finely crenulated. Length of type, 72 mm.; height, 95 mm.; diameter, about 40 mm. The right valve of this species resembles that of the preceding species in general outline and convexity, but it differs from it in having imbricated instead of ridged ribs and in having a more conspicuously crenulated margin. Another specimen from locality 2143 has a more irregular left valve, with a portion of the right valve showing a small part of the surface covered with imbricated ribs. The inner margins of the left valve of that specimen are conspicuously crenulated from a point near the beak to the base of the shell.
The exact locality within Silverado Cañon from which the type specimen (no. 12277) was obtained is unknown. Horizon.— Chico group, Actaeonella oviformis zone.» EARL LEROY PACKARD, 1922
|