WHITE.] CRETACEOUS FOSSILS. 9 
seen somewhat edgewise from above, and bearing a row of very small 
short spines. Ventral side unknown. The specimen is not well pre- 
served ; perhaps I should call it Ophiolepis bridgerensis.” 
CONCHIFERA. 
Genus OSTREA Linneeus. 
OSTREA SOLENISCUS Meek. 
Plate 11, figs. 2 a and b. 
Ostrea soleniscus Meek, 1873, An. Rep. U. 8S. Geol. Sur. Terr. for 1872, p. 487. 
The name of this species was given by Mr. Meek in a catalogue of fos- 
sils, on page 276 of the Annual Report of this Survey for 1871, but as 
no description or diagnosis then accompanied it, the name can date 
only from 1873, when his description was first published (loc. cit.). The 
following is Mr. Meek’s diagnosis of the species, together with his remarks 
upon it: 
“Shell attaining a large size, becoming rather thick in adult ex- 
amples, generally straight, greatly elongated, and comparatively very 
narrow, with parallel lateral margins. Lower valve with moderate 
internal cavity, and having the appearance of a little gutter or elon- 
gated trough; beak usually nearly straight, rather obtusely pointed, 
and more or less distorted by the scar of attachment; ligament-area of 
moderate size, strongly striated transversely, and provided with a large, 
deep, longitudinal furrow; surface apparently only with moderately dis- 
tinct marks of growth. Upper valve almost flat externally, but nearly as 
concave as the other within; beak usually a little truncated; ligament- 
area marked with strong transverse strive, and having its mesial ridge 
very prominent, and occupying as much as one-third its breadth. Sur- 
face as in the other valve, or perhaps a little smoother. 
“Length of adult examples about 18 inches; breadth of the same 
about 2.50 to 3 inches. 
“Although not a very uncommon species, I have seen no entire speci- 
mens of this remarkable shell. It will be readily known by its unusu- 
ally narrow, elongated, and generally straight form. The shell is usually 
found broken into several pieces, but casts of the internal cavity are 
not unfrequently met with entire. One of these now before me is nearly 
one foot in length and only two inches in breadth. It often had a curi- 
ous habit of growing in groups of three shells, attached to each other by 
the backs of their beaks. I have seen large numbers of them closely 
arranged, or nearly in contact with each other, at Coalville, all with 
their beaks downward, or at right angles to the plane of the sandstone 
strata. When found where it has grown isolated, the shell is sometimes 
arched to one side. 
“Tocality and position.—This species ranges through nearly the whole 
thickness of the Cretaceous sandstones near Coalville, Utah, and is also 
found in the Cretaceous coal-bearing sandstones at Bear River City, 
Wyo., as well as in the sandstone ridge of the same age on the Union 
Pacific Railroad, a few miles east of the latter locality.” 
I have frequently collected specimens of this species in the region in- 
dicated by Mr. Meek, and have verified all his observations as given 
above, but no specimens more perfect than his types have ever been dis- 
covered. While a large majority of the specimens have the long slender 
