Haworth. | Detailed Geology. 85 
The abundance of this secondary flint is difficult to com- 
prehend by one not familiar with the mines. ‘Travel where 
you will throughout the entire Galena-Joplin area and the 
great mass of the. dump;piles, aggregating so many millions 
of cubic yards, is composed almost entirely of, the primary 
flint fragments cemented together by the variously colored 
secondary flint. Its abundance is measured only by the 
abundance of the primary flint already described. 
Structure. 
The general structure of the limestone and flint in the 
Galena mining district has been hinted at already. Broadly 
speaking it is a stratified structure, with the limestone and 
flint intimately interbedded. Here and there large masses of 
flint seem to interrupt or destroy the bedded structure, leaving 
little, if any, approach to common bedding. Such is par- 
ticularly the case in the central part of the Galena district, 
that is, along Short creek valley between Empire and Galena, 
and practically throughout the entire hill on which Galena 
rests, and southward to the Standley diggings on Shoal creek. 
So far as the writer has observed from a study of underground 
conditions, bedding has been either so exceedingly rare here, 
or spaces between the layers so completely filled with other 
material, that the bedding structure cannot be observed at 
all or only to a limited degree. But eastward, practically 
throughout the southeast corner of the eighty acres belonging 
to the South Side Mining Company, great masses of flint are 
bedded one layer above the other, with spaces between the 
layers more or less completely filled with zinc ore. In one 
mine operated by Col. W. B. Stone some years ago, this was 
so noticeable that masses of zinc ore when lifted to the sur- 
face seemed to show broad bedded structure on account of 
their having been produced in the spaces between the layers 
of flint. What caused such openings was difficult to deter- 
mine. To a limited extent the vertical seams in the flint are 
filled with ore also, showing that they antedate the ore bodies. 
But here the vertical fractures were not nearly so numerous 
as in other places, and comparatively large pieces of flint rock 
