1895. ] NEW YORK ACADEMY OF SCIENCES. 61 
trend in each case is quite as sharp as that of the Limestone 
Hills* in the Choctaw nation. This similarity is so striking 
that one is tempted to imagine that the Ouachita folds within 
Arkansas, when followed out in detail, may be found to show a 
northward bend in their trend and may prove to be connected 
with some system of folds in Missouri, so that the Ouachita 
may resemble the Appalachian in a general northeastward and 
southwestward trend, but with the east and west portions pos- 
sibly longer than the north and south. 
Thus far no reference has been made to the granitic area and 
the Arbuckle mountains west from the Missouri, Kansas and 
Texas railroad in the Chickasaw nation. The writer had no 
opportunity to examine any except the western portion of that 
region. He is inclined, however, to regard it as belonging to 
an older system of folds and as wholly independent of the 
Ouachita, its peculiar structure and singular complexity being 
in striking contrast to the beautiful simplicity of the Ouachita. 
Undoubtedly it was affected by the post-Carboniferous elevation 
of the latter system, to which much of the distortion of dips 
may be due. To the same cause, indeed, may be attributed the 
contradictory dips and trends exhibited by the Carboniferous 
rocks near Dougherty, on the Santa Fé railroad. 
The Chickasaw region between the Missouri, Kansas and 
Texas, and the Gulf, Colorado and Santa Fé railroads deserves 
careful investigation. The only examination, thus far made, is 
the reconnaissance by Prof. Hill, which, considering the difficul- 
ties under which it was made, was singularly fruitful in results 
The second paper of the evening was read by Prof. J. F. 
Kemp, “ Zine and Lead Mines in Southwestern Virginia.’’ 
The paper was based upon a visit of the speaker to the mines 
the past summer. It showed their geographical distribution 
and the general geology of the country. By means of lantern 
views from photographs taken on the spot, the excessive sub- 
aerial decay of the blende bearing limestones was made clear, 
and the occurrence of the zinc in the shape of calamine as crusts 
upon the decomposed limestone and beneath the overlying 
‘mantle of clay. It was stated that the chemical reaction which 
had lead to the formation of the ore must have taken place at 
the ordinary poere; and one to the influence of the 
* These have been selected as they are the Seen fonostapbic te rae, of the region 
The structure is shown equally well by other members of the section, of course. 
