ckagin.] GEOLOGY OF THE REGION. 15 
blocks by weathering along- joint planes and bed planes in such a 
manner that it is not always very obvious which set of planes repre- 
sents the dip except as this is indicated by underlying strata. It is 
impossible to say what thickness it may have had here formerly, as 
an unknown part of it has been removed by erosion. 
At its base in the Trio the Kappa limestone presents a zone several 
i'vvt thick, composed almost wholly of spherical, oval, or somewhat 
irregular concretions, from 1 to 3 or finches or occasionally more in 
diameter. They consist of alternating lighter and darker layers, 
each a few millimeters thick, and sometimes weather uniformly with 
the matrix, being then seen in section, or are harder than the inclos- 
ing rock, when they are weathered out as pebbles, splitting sometimes 
into hemispheres which show the concentric layers. This is only an 
exaggerated sort of pisolitic structure. It is probable that this hori- 
zon, like others of the Malone formation, is variable, and that piso- 
litic structure is only locally developed in it. This rock is very 
probably similar to the pisolitic limestone conglomerate mentioned 
by Mr. Tail as constituting No. of his Malone Mountain section. 
A reconnaissance was made of the western segment (.1, B) of the 
Malone Hills, consisting chiefly of limestone and gypsum, with sand- 
stone at; its western end (as described by Mr. Robert W. Goodell in 
connection with his section of the Malone Hills) & and at least one 
remnant of conglomerate at its southern border; also of a ridge of 
quartzitic sandstone, apparently below the adjacent gypsum, and 
which forms an eastern foothill of Malone Mountain at the southern 
end of the mountain, and of portions of the eastern slope and sum- 
mit of the mountain. But as these w 7 ere for the most part only cur- 
sorily examined, and yielded no fossils except at one locality in the 
eastern slope of the mountain, no attempt will here be made to cor- 
relate positively their stratigraphic subdivisions with those observed 
at and southeast of the Trio. 
Provisionally, however, it may be said that if the gypsum near the 
southwestern base of hill G represents the same horizon as the heavy 
bed that traverses the western segment of the Malone Hills, and if the 
latter is but a reappearance of the great gypsum bed the upper limit 
of wdiose outcrop disappears by descending northerly from the south- 
ern east front of Malone Mountain, then the following inferences 
would apparently be reached : 
(1) That the same gypsum, though not exposed there, probably 
underlies the highly fossiliferous sandstones and limestones of the 
rheta at the east end of the Trio and at the Truncate mound. 
(2) That the w^ell-stratified limestones and the massive remnant of 
conglomerate lying above this gypsum and bordering it on the south 
<* Second Ann, Rept. Geol. Survey Texas, pp. 722, 723. "Jour. Geol., vol. 5, p. 817. 
