266 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
ornamentation about the pedicle groove and in having the anterior two-thirds 
marked by concentric lamellae in pairs. 
SCHIZAMBON DUPLICIMURATUM Hudson 
Plate 13, D, figure 6; plate 15, B, figures 5, 6 
Schizambon duplicimuratus Hupson, Rep. New York State Paleont. for 1903, p. 284, pl. 5, 
figs. 6, 7, 1904.—Raymonp, Ann. Carnegie Mus., vol. 7, No. 2, p. 228, pl. 34, figs. 23-24, 
I911.—T WENHOFEL and WHITING, Geol. Soc. Amer. Special Pap. 11, p. 45, pl. 7, fig. 16, 
1938. 
Figured specimens.—117954; A.M.N.H. (no number). 
Horizon and locality—Crown Point formation in New York: At Crown 
Point, Valcour Island, and Chazy. 
Mingan formation: Mingan Islands, St. Lawrence River, Quebec. 
Discussion.—This species suggests S. cuneatum in the presence of paired con- 
centric lines, but it is smaller, rounder, and the median sulcus of the brachial 
valve does not reach the margin. 
A pedicle interior in the collection is referred to this species, but the struc- 
tures are not well preserved. The foramen is located about 2 mm. anterior to 
the posterior margin and enters the valve in the median part of a considera- 
ble callus development occupying the posterior half. Anterior to this callus and 
near the lateral margins occurs a pallial trunk. Muscle marks are not clearly 
visible. The specimen comes from the St. Martin formation, $ mile north of 
Cap St. Martin, Quebec, Canada. 
SCHIZAMBON HIRSUTUM Cooper, new species 
Plate 15, D, figures 18, 19 
The material on which this species is based consists of a fragmentary pedicle 
valve and a nearly complete brachial valve. The specimens are large for the 
genus. The remains of the pedicle valve indicate an ovate shell with a long and 
large foramen and pedicle growth track. The brachial valve is nearly circular 
in outline as usual for the genus. The median sulcus is narrow but deep in the 
umbonal region, widening anteriorly and becoming lost in the general convexity 
of the valve near the middle. The surface of both valves is marked by many 
moderately closely spaced lamellae that are ornamented by numerous crowded 
and very small spines, measuring about 2 mm. in length. The holotype (brachial 
valve) is 12 mm. long, but probably at least 3 mm. are missing from the anterior ; 
width 11.8 mm. 
Types.—Holotype: 109670a; paratype: 109670b. 
Horizon and locality.— Murat formation, Whistle Creek, Va.: Along road and 
ridge, 2 miles northwest of Lexington, Lexington (15’) Quadrangle. 
Discussion.—This species is suggestive of S. cuneatum but differs in having 
concentric rows of fine spines and in not showing the paired concentric lines char- 
acteristic of that species. 
