LOWER CRETACEOUS DEPOSITS CALIFORNIA AND OREGON

124 lower chetaceous deposits ijf california and oregon
basal margin usually regularly curved, sometimes nearly straight; ends gaping;
posterior end widest, surface marked by rather large, irregular, concentric ribs."
The holotype of this species is in the Museum of Paleontology, University of California.
Stewart gives the following measurements of this specimen: leagth, 52
mm.; height, 37 mm.; thickness of both valves, 20.4 mm.
Although Gabb does not mention the diagonal depression extending obliquely
downward from the beak to the posterior basal border, it is shown in his figure and
Beems to be characteristic of the shell of this species. A slightly smaller example of
the specieB was found in the uppermost beds of the Horsetown group at Locality 1341
(Calif. Acad. Sci.), at the site of old Hometown, Shasta County.
It agrees in all respects with tbe description and figure given by Gabb, and has
the following dimensions: length, 48 mm.; height at beak, 30 mm.; thickness of both
valves below beak, 21 mm.
The oblique depression begins near the top of the beak and reaches the base at the
posterior basal angle. Larger examples have been collected at the same place, where
it ia commonly associated with Puicwta hoffmanni (Gabb), fieudanlteeros brtweri
(Gabb), and Sonneraiia stantani Acdcraon.
Patwpe tubacquilaieralit Anderson, n. sp.
(Hate 3, figure t)
Shell of medium size, oval in outline, nearly smooth; beaks a little in advance
of tbe middle, incurved, approximate, low, rounded; dorsal margin sloping gently
backward, slightly concave; anterior dorsal margin, sloping more steeply; anterior
margin narrow, abrupt; posterior margin broader, gently rounded; surface marked by
faint growth lines and also by weak undulations about the beaks; no oblique depression
visible; ends narrowly gaping.
The holotype (Calif, Acad. Sci. type Coll.) was obtained at Locality 1344 (Calif,
Acad. Sci.) at old Horsetown; height, £5 mm.; length, 88 mm,; thickness of left
valve, 16 mm.
Paiwpc thaelacoht Anderson, n. sp.
(PUUi 3, 6(um 7)
Shell of medium size, quadrate in outline, short, nearly as high as long; beaks
small, situated near anterior end, incurved, approximate; dorBal margin slightly
concave; anterior margin steep, curving to rounded anterior border; surface marked
by strong depression extending obliquely backward from the beak to the posterior
basal angle.
The holotype (Calif. Acad. Sci, type Coll.) measures as follows: length, 58 mm.;
height below beak, 48 nun.; thickness of both valves, 30 mm.
Four examples of this species were obtained at Loc. 1344 (Calif, Acad- Sci ) at
old Horsetown, with Beudaniieeras breweri, B. kaydeni (Gabb), and many other
species, In outline and surface markings the species resembles Peuiopc vumdibitSa
d'Orbigny, but the resemblance may be superficial and not actual,
PWOLADIDAE Fischer
Turnus Gabb
7"wmti» plexus Gabb
Turnua plenus GAOB, Paleont. Calif., vol. 1, 1864, p. 146, pi. 22. fig. 116; North fork
of Cottonwood Creak, Shasta County; vol. 2, 1869, p. 233—STBWAKT, Phila.
Acad. Nat. Sci., Spec. Publ. no. 3,1330, p. 296, pi. 4, fig. 3; Locality not known.
Tbe "leetotype" (? holotype) of this species is in the Museum of Paleontology,