ARNOLD — THE PALEONTOLOGY AND STBATIGRAPHY OF SAN PEDRO. 171 



This is tlie coramon Donnx of the West Coast, and is easily recognized by its 

 triangular shape and the short, straight, posterior end. This species has been 

 erroneously called californicus by Carpenter and others since then, but a comparison 

 of one of these shells with Conrad's original figure and description of cnlifnrnica 

 readily shows the error. The true californica Conrad has a rather produced and 

 rounded posterior end, and is much narrower than kevigata. S})eeimcns identified 

 by Dr. Dall. 



Rare in the lower San Pedro series at San Pedro and Dcadman Island; 

 coramon in the upper San Pedro series at San Pedro, Los Ccrritos, Crawfish George's, 

 Long Beach, and Dcadman Island. Found also in the Pleistocene at Barlow's ranch, 

 Ventura; and at Spanish Bight, Twenty-sixth Street, and Pacific Beach, San Diego. 

 The specimen figured is from the upper San Pedro series at San Pedro, and is now 

 in the collection of Delos Arnold. 



Living. — Monterey?; San Luis Obispo to San Diego (Cooper). 



Pleistocene. — San Pedro to San Diego (Cooper): San Pedro; San Diego; 

 Ventura (Arnold). 



Superfamily SOLENACEA. 



Family XXXIV. SOLENID.E. 



Genus Solen Linne. 



Hinge with one cardinal in each valve; beaks nearly anterior; external surface polished; 

 valves usually straight. 



Type, Solen marginatus Pulteney. 



120. Solen rosaceus Carpenter. 



Solen {sicarius ? var.) rosaceus Cpr., Brit. Assn. Rept., 1863, p. 638; Ann. & Mag. Nat. Hist., 



3rd Sen, Vol. XV, 1865, p. 177. 

 Sole7i rosaceus CvK., Cm KBh, Pal. Cal., Vol. II, p. 88, 1869. Cooper, 7th Ann. Rept. Cal. St. 



Min., 1888. p. 265. Keep, West Coast Shells, p. 202, 1892. Williamson, Proc. U. S. 



Nat. Mus., Vol. XV, 1892, p. 1S4. Dall, Trans. Wagner Inst. Sci., Vol. Ill, Part 5, 



1900, p. 952. 



Shell of medium size, long, subcylindrical, slightly falcate, margins parallel, ends gaping; 

 beaks terminal; anterior extremity evenly rounded, projecting furthest a little below the middle; 

 posterior extremity very long, evenly rounded; hinge-teeth, one in each valve; ligament long, ex- 

 ternal; anterior muscle-impressions elongated; posterior oblong; sinus with squarish corners. 



Dimensions. — Long. 55 mm.; alt. 10.5 mm.; diam. 6 mm. 



This species much resembles S. sicarius but is much longer and narrower, 

 more cylindrical, and has a much more evenly rounded and less abruptly truncated 

 anterior extremity. Found also in the Pleistocene at Spanish Bight, San Diego. 



Living. — Santa Barbara south to Gulf of California (Dall). 



Pleistocene. — Santa Barbara (Cooper): San Pedro (Arnold): San Diego 

 (Dall; Arnold). 



