648 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
profile with the greatest curvature in the umbonal region; umbo slightly sulcate, 
somewhat swollen on the sides; fold low posteriorly but strongly elevated an- 
teriorly ; rounded in profile with the median 2 costae standing above the flanking 
ones ; anterolateral extremities depressed toward the pedicle valve; flanks mod- 
erately convex, posterolateral slopes nearly vertical. 
Measurements in mm.— 
Length Width Thickness 
PRGIGE YO E cca. io he cis AES av ctatoympaisys ess wieiciee 13.6 15.4 9.1 
Paratype (Carnegie Mus. 2174)............ 12.2 13.0 8.2 
Types.—Holotype: Carnegie Mus. 2176; figured paratypes: Carnegie Mus. 
2174, 2175, U.S.N.M. 117225; unfigured paratypes: Carnegie Mus. 2172, 2173, 
2177-2179. 
Horizon and locality—St. Martin formation in Quebec, Canada: St. Martin 
Junction, near Montreal. 
Crown Point (or Valcour) formation in New York: On Valcour Island, Lake 
Champlain, Plattsburg (15’) Quadrangle. 
Discussion —This species differs from FR. orientalis (Billings) in its less cari- 
nate fold which is much less elevated anteriorly and has a proportionately shorter 
tongue. The anterolateral extremities of R. orientalis are much more narrowly 
rounded than those of the shell from St. Martin Junction. Furthermore, R. orien- 
talis attains only about half the size of FR. raymondi. 
ROSTRICELLULA ROSTRATA Ulrich and Cooper 
Plate 131, B, figures 8-16; plate 131, F, figures 40-46; plate 136, B, figures 23-34; 
plate 136, C, figures 35-49 
Rostricellula rostrata UtricH and Cooper, Journ. Paleont., vol. 16, No. 5, p. 626, pl. go, 
figs. 24, 28, 20, 32, 37, 1942. 
Shell of about medium size for the genus, triangular to subpentagonal in out- 
line ; brachial valve slightly deeper than the pedicle ; beak forming approximately 
a right angle; greatest width at or slightly anterior to the middle; anterolateral 
margins narrowly rounded, front margin broadly rounded. Surface costate, 3 
to 5 costae occupying the sulcus and 4 to 6 defining the fold; flanks marked by 
6 costae. Entire surface marked by fine radial and concentric lines that produce 
granules where they intersect. 
Pedicle valve moderately convex with the greatest convexity located from the 
middle to the umbo. Posterior quarter and umbonal region moderately convex ; 
sulcus originating about 6 mm. anterior of the beak, flat in profile, shallow, and 
producing a short truncated tongue anteriorly. Sulcus occupies more than half 
the width at the front. Flanks gently convex and with moderately steep slopes 
to the margins. 
Brachial valve evenly and strongly convex in lateral profile and strongly con- 
vex in anterior profile; greatest convexity near the middle. Umbonal region 
swollen; the fold originates about 5 mm. anterior to the brachial beak; posterior 
to the fold a shallow and poorly defined sulcus marks the shell. Fold low, spread- 
