88 MALONE JURASSTC FORMATION OF TEXAS. [bull. 26f 
A cast of Martesia referred to this species, obtained at the anticlin< 
in the ens! side of Malone Mountain about 1 mile north of its souther! 
end, shows a more posteriorly produced form than might be inferra 
from the above-described types, indicating that a considerable lengti 
has been broken oil' from each of the latter. 
Borings presumed to have been those of Martesia were also foum 
1! miles east of Malone station. 
GASTROPODA. 
PLEl'Kt )T< )MARII1 KK. 
Genus PLEUROTOMAKIA Defiance. 
Plei R0T0MARIA circumtrunca sp. n. 
PI. XIX. flgs. S, !>. 
Shell conical, consisting <>f .'> to 6 flattened or in part, concavo 
whorls, the slope of spire nearly straight, that of the entire shell, how 
ever, concave, owing to the form of the body whorl; spire acute 
sutures lightly impressed, bordered by a low elevation above am 
below; body whorl concave above the peripheral zone, its periphery 
canaliculate-truncate, or having two low. abrupt angulations with j 
narrow, shallow -concave bell between them (and which, in the poorly 
preserved and sometimes more or less distorted specimens common]! 
found at the type locality, occasionally appears Like a merely flail 
truncation); surface of the entire shell ornamented with fine 
crowded, revolving raised lines, so minute as to be scarcely visible to 
l lie linked eye and of which (in one of the types) there are 11 on tin 
peripheral canal of (he body whorl. The aspect of the peripheral! 
canalicular truncation Ls outward and slightly downward. 
Measurements. Height, 20 mm.; breadth, L9 mm.; angular diver- 
gence of (lie slopes (excluding the body whorl), 66 . 
Occurrence- One and a half miles east of Malone station, in tin 
lower part of the Theta subdivision of the section there exposed ; witl 
Delphinula stantoni, Turbo? beneclathratus, Natica williamsi, NeriU 
nodilirata : Gervillia corrugata, etc. Represented by eleven examples 
TR< )( 1 I II I )^E. 
Genus TURBO Linnaeus. 
Tl RBO ( BENECLATHRATUS Sp. U. 
PI. XIX. flgS. 10, II. 
Shell rather small, (orbinate-conical, composed of about 4 ventri- 
cose whorls; spire and body whorl about equal in height; body whorl 
