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THE soil of this region is in general very coarse. Typically, it is composed of decomposed granite material, but it also includes, particularly along the margins, soils originating from the weathering of rocks representing all gradations of metamorphosis between crystalline rocks and sedimentary sandstone and limestone. The coarse granite soil typically overlies virtually unfissured massive granite whose uneven surface causes it to protrude more or less as solid, soil-less exposures grading from scant elevation and negligible area to hills several hundred feet high and several hundred acres in extent. Granite Mountain in Burnet County and Enchanted Rock in Llano County are conspicuous examples of major exposures.

The tighter, finer textured and more level portions of this region are characterized by mesquite with more or less of an admixture of Condalia, Zizyphus, Mimosa, cacti and a few other chaparral representatives, together with liveoak and cedar; looser, coarser soils of a rougher topography, by black jack and post oak with some hickory. These latter occur even in the deeper, soil-filled, seep-watered crevices between delaminate granite blocks split off from the massive sub-stratum of such protrusions as Enchanted Rock and Granite Mountain. In such locations the plants are quite scrubby and wholly devoid of any trunk below the branches-that is, the branches begin at the ground surface-and the height is seldom more than 12 or 15 feet. Among other woody species occurring well up on such hilly eminences are Mexican persimmon, buckeye (Aesculus arguta), Mexican buckeye and hackberry.

In deep narrow ravines opening to the northwest, well watered by continuous seepage and protected by steep slopes from the effect "

Crystalline rocks are old rocks altered during a former period of deepburial. They include both igneous (formerly molten) and sedimentary rocks.

Weathering of granite outcrops proceeds by the splitting off, or wearing off, of thin shells or "laminae." The result of such continued "delamination" is to produce smooth, oval, to round outcrop boulders and masses of granite.