BUILDING STONES. 643 



longing to the Texian System, shading from a quartzose granite into a gneissic 

 or feldspathic sandstone. Their best exposures are along the borders of the 

 great granite basin. As building material they are of no particular value. 



THE MIXED GRANITES. 



This type is represented in the areas of Silurian granite. It is a distinct- 

 ive feature in certain localities, and I have always found it to hold the same 

 relations to the Post-Silurian uplifts wherever visible. In the Wichita Moun- 

 tains, Indian Territory, it manifests identical features. There are some por- 

 tions which might properly be regarded as forming a separate class of gray 

 granites, and among these some excellent material may be quarried. The 

 ordinary outcrops are made up of a coarse, but tough, quality of rather quartz- 

 ose reddish granite, in which are inclusions of gray granite, cyanite, black 

 schists, and other material of irregular dimensions. Such masses will not 

 usually prove profitable in the working, although the texture and color of 

 the matrix often leave little to be desired. The indeterminate arrangement 

 of the inclusions makes this material at least of doubtful utility except for 

 local uses. Possibly, however, some very desirable combinations of color for 

 ornamental purposes might be secured at the cost of much labor and time. 



The best exposures are in Silver Mine Hollow and Beaver Creek, in Bur- 

 net County; in the apparent extension of the same belt in the Pedernales 

 Valley, Blanco County; on Honey Creek north of Packsaddle Mountain, 

 Llano County; and in the drainage area of Upper Honey Creek, Mason 

 County. Possibly the fine exposures of gray granite within a few miles of 

 Enchanted Rock, in Llano and Gillespie counties, may also belong to the 

 same set, but the most of this properly comes under the next head. 



THE DIMENSION GRANITES. 



Some of the material heretofore described in special situations where it has 

 been hardened by proximity to more recent outbursts, may yield blocks of 

 sufficient size to be used as columns, and for the grosser objects of building 

 and decoration, but such cases are exceptional. The best source of granite 

 for constructive purposes, including foundations, superstructures, and the 

 heavier ornamentation, as well as mural and monumental works, is the "Bur- 

 net granite," as it is popularly termed, from the customary source of supply 

 in Burnet County, near Marble Falls. Its general excellence and the wide 

 range of its adaptability, no less than its durability, pleasing appearance, and 

 other admirable qualities, are well exemplified in the Texas State Capitol and 

 in the Alamo Monument at Austin. A very considerable extension of the 

 applications of this granite has been made within the past year. There is an 



