284 J. P. Kimball—Grahamite in the Huasteca, Mexico. 
it appears that the fissure must have been made at the time 
the elevation of the shales, and soon afterwards filled wi 
asphaltum, which continued to form after it had been filled. 
That no great period was required for this operation, is shown 
by the fact that the overlying conglomerate also conforms to 
the stratification of the shales as well as to the outline of the 
overflow of the grahamite, locally intervening. 
The occurrence of such a fissure in shales so imperfectly hard- 
ened, and so easily weathered, affords another proof that the 
filling of the fissure immediately followed its formation, that is, 
after the emergence of the shales and before the deposition of 
the overlying alluvium. It is from this evidence of the direct 
sequence of terranes, and the relation thus established with sub- 
sequent alluviums that, in the failure of the evidence of their 
fossils, I refer to the Tertiary the grahamite-bearing shales of 
the Capadero basin. These are probably remnants of the littoral 
Tertiaries of eastern Mexico and Texas.* : 
The strike of the fissure is nearly north and south, directly 
across the river. No attempts have been made to trace It 
beyond the excavation near the water's edge, its character as 4 
fissure not having been recognized previous to my visit 
length of about 300 feet upon it had at that time been 
of chapapote or asphaltum. Numerous deposits are said to 
occur aed of the Pecan River. One deposit, which I visited, 
is found on the Tanelul Ranch, occupying an elevated basin oF 
cul-de-sac between two hills of the Alacranes range, here — 
ing the boundary of the Capadero valley. The pomt ae 
24 leagues east of the Cristo mine, and directly mm range WUS’ 
course of the Cristo fissure as far as traced. The chap eee 
accumulated from the evaporation of liquid maltha, whieh 
. : . ber of orl 
issues in the form of a sluggish spring with a ; wie the above 
inally formed. 
and forced 
issued from the depressed portions of this formation, and a the 
