52 MALONE JURASSIC FORMATION OF TEXAS. [bull. 26Q 
The hinge characters of this shell are unknown. While the gen- 
eral form permits little doubt that it is one of the Arcidse, there isj 
less certainty of its generic position, and it is placed only provision-] 
ally under Area. 
The species is named for Mr. E. T. Dumble, late State geologist of] 
Texas. 
Genus CUCULLiEA Lamarck. 
CTJCULLiEA? TEXTIGOSTATA S]). U. 
PI. VI. QgS. <>. 10. 
Shell ventricose, short, subtriangular, somewhat pointed inferol 
posteriorly, rounded anteriorly, the posterior slope flattened anfl 
making an angle with the outer slope; beaks well inflated and ele- 
vated; entire surface marked in a crowded manner with radiating! 
linear costelhtt and in large part with erect concentric lines of imbri-j 
cation, of which the Latter are the liner and more crowded (seen to 
advantage only when magnified), and the former the more conspicu- 
ous and more persistent under weathering. A considerable part of 
the surface when magnified appears woven, like cloth or miniature 
basket work, except for the alternating arrangement seen in the' 
latter. This woven ornamentation resembles that seen in Area taffii 
the radial costelhe being, however, much liner and more numerous 
than in that anteriorly and posteriorly otherwise ornate and alto- 
gether differently shaped arcid. 
Measurements. — Height, about •_''.> or 30 mm. (?) ; length, 34 mm.; 
breadth, 24 mm. 
Occurrence. — One specimen and a fragment of a second; H miles 
east of Malone station. 
In the absence of any knowledge of (lie hinge of this shell it is not 
possible to be sure whether it i^ a Cucullsea or an Area. The orna- 
mentation — primarily radial and secondarily cancellated — is of a 
type more common in the latter genus: but the species is put provi- 
sionally in Cucullsea, under the subgenus Trigonarca, on account ol 
its triangular form. 
ClJCl LL2EA TRANSPECOSENSIS Cragill. 
Cucullwa transpecosensis Cragin, 1803; Fourth Ann. Rept. Geol. Surve: 
Texas, ]>t. 2. p. 17.". 
The genus Cucullaea is not represented by abundance of individual! 
in any of its species in the rocks of the Malone formation in Texas 
and so rare is the massive and ventricose 0. transpecosensis that 
despite careful collecting for many days at the locality which yielde< 
Messrs. von Streeruwitz and Wyschetzki the type, the latter stil 
remains the only specimen known of this species. 
