10 MALONE JURASSIC FORMATION OF TEXAS. [bull. 2GG. 
HISTORY OF GEOLOGICAL STUDIES. 
The geological observations made along this part of the Rio Grande 
Valley in the fifties by the Mexican Boundary and Pacific Railway 
surveys were but cursory, and did not specifically include the Malone 
district, and the first serious geological study within the district was 
made in 1890 by the Geological Survey of Texas, under Mr. E. T. 
Dunible. In that year Mr. J. A. Tail', then attached to Mr. W. II. 
vmi Streeruwitz's Trans-Pecos division of that survey, studied Malone 
Mountain, and Mr. Ralph Wyschetzki, of the same division, collected 
a few fossils from the hills northeast of it. Tn the second annual 
report of the same survey, issued in L891, Mr. Tall published and dis- 
cussed a section of Malone Mountain and described, with scant allu- 
sion to its paleontology, an essential pari of the Malone formation, 
consisting of limestone, gypsum, and flagstone of Malone Mountain, 
which he called the " Malone beds." lie thus virtually recognized 
the formation, his name for which, as the earliest proposed for it, is 
here retained; but lie erred in placing it in the Washita Cretaceous: 
division together with his Etholen and Yucca beds, which are typi- 
cally seen in a part of the Etholen Knobs and Yucca Mesa, and are of 
Glen Rose age. Mr. Taff also correlated the sandstone and oyster- 
shell breccia of the Etholen Knobs with the Malone formation, but 
these, like the Etholen breccia-conglomerates and the Yucca beds, be- 
long to the Glen Rose alternating beds. 
In L893 I described the better part of a small collection of fossils 
which Mr. Wyschetzki had obtained from the hills northeast of Ma- 
lone Mountain. Disregarding for the moment a strong suspicion 
that these fossils were Jurassic, I described them as Cretaceous, 
since the time and material then available were too limited for a 
conclusive study, and since it was thought that the small Malone 
fauna then known had one species in common with the Cretaceous, in 
Trigonia taffli, which occurred with undoubted Cretaceous fossils on 
Bluff Mesa and was supposed to have been found in the Malone dis- 
trict also. ?> Put I resolved to take up the question at the first 
opportunity that should offer. 
°A contribution to the invertebrate paleontology <>f the Texas Cretaceous: FourtH 
Ann. Kept. Geol. Survey Texas, pt. 2, pp. i-iv, 139 246, and Pis. XXIV XLVI. 
6 The material thus treated included six new species, which were described under die 
following names : Anatina tosta, Cucullcea transpecosensis, Cyprina streeruvitzii, Trigonii 
vyschetzkii, Trigonia taffli, and Venus i>i<ih>n< asis. it was afterwards found dial Triga 
nia taffii does not occur at all in the Malone formal ion. hut is a fossil of the Glen Roal 
alternating beds, to which Bluff Mesa belongs. The type material of '/'>i<j<>)ii<i taffii was 
described (loc. cit., |>. 214) as having come in part from Bluff Mesa and in pari from the 
locality of Trigonia vyschetzkii, east of Malone. It is now. however, practically certain 
that the nearly complete valve from Bluff Mesa alone represented Trigonia t<:f]ii, and that 
all of the framiieiit.il material which was supposed to belong to this species, and which 
was from the Malone locality, belonged — as pari of it which I recently had opportunity 
of reexamining certainly does — to T. vyschetzkii. All of the very diligent collecting done 
at the Malone locality by Doctor Stanton and myself, while showing the occurrence of V. 
