DEVONIAN SPECIES. 39 



intermediate gradations in this character, I have preferred to regard those 

 showing this difference as more probably mere varieties of the variable 

 species reticularis. The question in regard to the specific identity or differ- 

 ence of such shells is one respecting which authors may well differ without 

 quarreling. 



Locality and position. — Pinon Station, Treasure Hill, White Pine Dis- 

 trict; Roberts's Creek ; and near Warm Springs, Upper Humboldt Range, 

 Nevada. Colonel Simpson also brought specimens, including both the finely 

 and more coarsely costated varieties, from latitude 39° 30' N., longitude 



115° 26' W 



SPIRIFERIDJ]. 



Genus SPIRIFER, Sowerby. 

 Spibipek Utahensis. Meek. 



Plate 3, figs. 1, 1 a, 1 6, 1 c, 1 (i, 1 e. 

 Spirifera NorwooM, Meek (1860), Proceed. Acad. Nat. Sci. Philad., XII, 308 (not S. 



Norwoodi, Hall). 

 Spirifera Utahensis, Meek (1860), note appended to extra copies of above-cited paper. 

 Spirifera Utahensis, Meek (1876) in Col. Simpsou's Report Expl. across the Great Basiu 

 of Utah, 345, pi. 1, figs. 4 a, b, c. 



Shell rather «mall, very inequivalve, distinctly convex, or sometimes 

 subpyramidal, with (as seen from above or below) its general outline form- 

 ing rather more than a semicircle ; length about one-half to two-thirds the 

 greatest breadth ; lateral extremities somewhat obtusely angular ; anterior 

 and antero -lateral margins forming together about a semicircular outline. 

 Ventral valve elevated at the umbo, and sloping off abruptly to the front 

 and lateral margins, with usually a slightly convex outline, especially on the 

 anterior slope, sometimes with one of the lateral slopes concave in outline 

 posteriorly; mesial sinus shallow, rather narrow, rounded within, ,and 

 extended to the apex of the beak ; beak elevated, abruptly pointed, and 

 slightly arched ; area high, or with height equaling about half its breadth, 

 triangular, and continued to the extremities of the hinge, with well-defined 

 or angular, lateral slopes, ranging at about right angles to the plane of the 

 shell, and usually a little arched; foramen proportionally very naiTow, 

 or sometimes twice as high as wide. Dorsal valve much depressed, or but 



