Texas Paiwozoic.— Tarr. 175 
* several thousand feet of strata above the Trinity, some of them 
of deep water origin. 
If, instead of being a moderately low lying highland, as I have 
attempted to prove, the central mineral district was a mountainous 
area of great hight and topographical diversity, it might still be 
an island in the Cretaceous sea. This seems more unlikely, how- 
ever, When we consider the comparatively small area of the dis- 
trict, or, at least, that part of it which cannot be proved to have 
been covered by Cretaceous by the existence of remnants of these 
strata: however, the continuation of this area along the Peder- 
nales river, ‘and probably elsewhere beneath the Cretaceous, shows 
that large parts of the older Palzeozoic rocks had by this time 
lost their former topographic diversity, and become reduced to 
highlands of moderate elevation and topography. In view of 
these facts it would be quite remarkable to find a single small 
area retaining its elevation to a sufficient degree to withstand the 
long continued and deep submergence of Cretaceous times and 
still remain an island, 
Aside from these facts there is another bit of evidence pointing 
to the same conclusion. With the exception of the lower Trinity 
‘beds the Cretaceous is quite without evidence, where I have seen 
it, of neighboring land. In the chalk and other beds the ma- 
terial is of such extreme purity that the neighborhood of land is 
quite out of the question, without the assumption of intermediate 
currents of sufficient rapidity to remove all land debris of even 
the finest quality. 
Dr. Comstock puts forward* several reasons for his belief which 
I wish briefly to consider. First, the absence of remnants of 
Cretaceous on the older Paleozoic is noted. This is certainly 
striking, but it may equally well prove that the Cretaceous has 
been for along time removed from this area, as I shall attempt to 
show possible. Upon the Carboniferous, low lying and undiversi- 
fied as it is, there are areas of considerable extent, only recently 
uncovered from beneath the conglomerate, in which, except in 
the stream beds, no signs of this covering exist. In the strongly 
diversified older rocks, with their greater elevation, this removal 
would be much more quickly and completely accomplished. 
Secondly. <‘‘The Cretaceous beds along the borders, even in- 
cluding the fossiliferous limestones, in large degree, are chiefly 
*Second Ann. Rep. Texas Geol. Survey, 1891, pp. 663-4. 
