Art. IX.] Herrick-Johnson, Geology of the Albuquerque Sheet. 209 
the smaller ones have nearly the form of L. elongata and have 
the surface preserved, showing it to be almost pustulate by rea- 
son of nodes developed upon the concentric striae. We doubt 
the possibility of separating these forms. The L. elongata form 
occurs also at Carthage (See Plate XXXIII, Fig. 5). 
Camp tone ctes symnietricus , sp. n. 
Shell small, not over three fourths of an inch in length ; 
broadly oval in outline ; hinge line imperfectly seen, apparently 
longer than half ef the width of the shell ; valves convex ; car- 
dinal slopes from the beak forming with each other nearly a right 
angle, straight ; surface of valves marked by very fine, numer- 
ous, irregular, hair-like radiating striae which curve strongly up- 
ward toward the margin, and also by fine concentric striae. 
In the gasteropod zone below the Tres Hermanos sand- 
stone in the Rio Puerco valley. None of our specimens pre- 
serve the hinge characters or extremities of the ears but the 
character of the sculpture is similar to C. burlingtonensis. 
Dosinia sp ? 
A cast from the same bed as the above is referred to Dosinia 
on the basis of a superficial resemblance to D. erecta, Whitfield. 
Gasteropoda. 
Chemnitzia coalvillensis. Meek. 
Plate XXVIII, Fig. 5. 
A small species, our specimens of which are insufficiently 
preserved, may be referred here. From the upper Fox Hills 
layers above the lignite. 
Chemnitzia sp. 
A somewhat larger form than the above, which we cannot 
at present determine, is from the septaria concretions near San 
Francisco. 
Gyrodes depressa^ Meek. 
Plate XXIX, Fig. 7a, b. 
The figure is not exactly correct in the representation of 
the expansion of the lower part of the body whorl. Most spec- 
