62 
MALONE JUKASSTC FORMATION OF TEXAS. 
[bull. 266. 
more or less vertically, and increasing rather rapidly in size from thj 
limiting angulation to the ventral and anterior borders, about twict 
as wide as the plain, flattish-concave intervals between them, theii 
summits obtuse and strongly and a little obliquely cross-striated i] 
such a manner that the striation is visible if the ribs are viewed tan- 
gentially from in front, but invisible if so viewed from behind. 
Measurements. — Height, 21 mm.; length, 30 mm.; breadth, 10 mm. 
approximately. 
Occurrence. — A single mold, representing the greater part of 
right valve in excellent detail, is the type and only known specimen. 
It was obtained by Doctor Stanton on the east slope of Malone Moun- 
tain, near its southern end, 200 or 300 feet above the gypsum bed that 
there forms the mountain's base. It lacks the escutcheon, the uppei 
part of the area, and the umbonal apex, but the exterior characters oi 
nearly all of the rest of the shell may be readily observed either in th( 
mold or on the gutta-percha squeeze taken from it. The species i> 
referred to the section Scabrse. 
Trigonia mi nita sp. n. 
PI. X, figs. 8-11. 
Shell ovate-pyramidal, of medium or rather large size among 
congeners, moderately ventricose, rather elevated; valves thick; are* 
strongly flattened, separated from the preareal surface by a veij 
large and prominent, obtuse, somewhat imbricated radial costa, pre 
w(\^\ by a furrow, the area! surface being ornamented with tw< 
rather strong, not widely separated, cariniform radial costa', whicl 
are separated from each other by an interval that is rather narrow as 
compared with that between either costa and the corresponding are* 
border, and several similar but smaller eostelhe or rays, there being- 
least two such rays in the anterior interval; preareal surface orm 
mented with (25 to 30?) strongly and rather abruptly elevated coi 
centric ribs, which resemble low walls, terminate almost abruptly 
the preareal furrow, and are in large part only about half as wide 
the flattish-concave intervals between them. 
Measurements. — These can not be exactly given, owing to the hnpci 
lection of the material, but about the following dimensions are appal 
ently indicated in one instance: Height. 70 nun.; length, 75 mm. 
breadth, 42 mm. In another the height is about SO mm. 
Occurrence. — Represented by three very imperfect specimens ai 
a number of characteristically ornamented fragments. One of tl 
specimens were obtained by Doctor Stanton near the south end of 
Malone Mountain, west face, near top, and another west of the mounl 
tain, about 2 miles west of Malone station. The remainder of thJ 
material is from the locality 1\ miles east of Malone station. All of 
