6^6 CENTRAL MINERAL REGION OF TEXAS. 



on hand and practically ready for shipment. In 1889, as shown by the cen- 

 sus returns, the granite industry in Texas did not pay expenses; but with 

 present facilities and their constant improvement, added to the rapidly in- 

 creasing demand for our granites, there is no question that good profits will 

 be made in future, especially as some of the largest quarries have heavy stocks 

 of marketable product which has already been included in the cost tables. 

 Some dimension granite has been quarried about four miles west of south 



from Llano by J. K. Finlay and by John Goodman. Rabb and and 



others have locally used some, which is very attractive, taken from the Cat 

 Mountains northwest of Llano. From Gillespie County granite, besides the 

 small workings of residents here and there, a respectable trade in monumental 

 material has been built up by Frank Teich, of San Antonio. 



THE FISSILE GRANITES. 



There are numerous granites which occur in narrow dykes and in slabby 

 or fissile plates, although this structure is especially characteristic of the latest 

 uplift in the strike north 50° east. Many of them are useless, owing to their 

 brittle character, or the loose arrangement of the mineral components, and 

 the difficulty of extraction in any considerable quantity. A few may be found 

 which will serve for ornamentation or for some other special application. The 

 material of the Sentinel Rock and equivalent ridges northeast of Enchanted 

 Rock is firmly cemented by a peculiar infiltration of porcelain quartz. This 

 might be utilized, perhaps, in artistic construction, if judiciously selected and 

 polished. So much of the fissile type occurs in close proximity to the large 

 mounds of dimension granite that the quarrying of it in connection therewith 

 might be made profitable, if the crumbling nature of the outcrops does not 

 continue much below the surface. 



Some of the tougher gneisses might be included in this category, but it is 

 not probable that they will generally have more than a local application as 

 building material. The fine-grained (euritic) granites of some portions of the 

 areas occupied by this class are very well adapted for ornamental trimmings 

 and to afford contrasts in structural design. 



B. MARBLES. 



Restricting the term to more or less altered limestones or dolomites, but 

 not excluding certain rocks which the trade would accept, although not 

 strictly such, the marbles may be conveniently grouped in three classes. The 

 differences are easily learned, although the ground of separation in the first 

 place is chiefly geologic. They are treated below in chronologic sequence, 

 beginning with the earliest formed. 



