mile 0.0 (30o 45.590; 98o 40.510) - Junction of 29, 16, 71
Low, relatively featureless topography is encountered for eight miles north of Llano, though pink granite and gneiss boulders are seen here and there. Nine miles north of town, Baby Head Hill is part of an east-west ridge which is held up by a hard igneous dike that stands above the surrounding Valley Spring gneiss. The dike can be seen in roadcuts on either side of the highway where the road cuts the ridge. The dike is composed of a striking gran-ite which contains red-pink feldspar crystals and blue quartz grains that float in a fine-grained, almost black groundmass. The rock is unusually hard, and was quarried at one time for building stone. The quartz is blue because of chromium impurities. Unique to this area, the rock is appropriately called Llanite. You really must get out of your car and examine this rock up close in the roadcut.
Most of the Llanite belt is on private property, but lots of it can be picked up alongside the highway, either north or south of the picnic area, as shown on the accompanying map. A few of the ranchers in the region allow collectors onto their property if arrangements are made in advance. You can obtain lots of material in the road-cuts, but if you would like to explore more undisturbed deposits on one of the ranches, contact the Llano County Chamber of Commerce, 700 Bessemer, Llano, Texas 78643; (915) 247-5354.
Farther north, the road passes from Precambrian igneous terrain into the fringe belt of Paleozoic sandstone and lime-stone. The Paleozoic rocks dip gently to the north and, from south to north, are stacked in proper sequence, oldest to youngest, Cambrian to Pennsylvanian. These sedimentary rocks were deposited on the beveled surface of Precambrian rocks. Watch for a roadcut on the right about four miles north of the Llanite dike, where the first Cambrian sandstone (Hickory sandstone) is exposed. Here, the gray-tan, pebbly, and very hard sandstone is shot through with thin calcite veins. This sandstone was laid down directly on the flat, eroded, Precambrian surface.
The landscape around the town of Cherokee is open and quite flat, but look for a quarry on the west side of the road a few miles north of town, where hard, glinty blocks of dark gray Cambrian-Ordovician limestone here are about 500 million years old.
A few miles farther, in the stream valley of Buffalo Creek, another very hard limestone crops out, the Ordovician Ellenburger group. Note it too is very dense, and has many chert nodules in it. The nodules are thought to be redistributed silica, derived from original layers of siliceous marine organisms, such as sponges and diatoms.
Abundant limestone boulders, weathered to a battleship gray are lying out in the fields, derived from the underly-ing beds of Ordovician age rocks. At Simpson Creek crossing, just south of the town of San Saba, thin limestone beds in the roadcuts are Pennsylvanian, a little over 300 million years old. This is Marble Falls limestone, named for ledges exposed east of here at the town of Marble Falls.
mile 0.0 (30o 45.590; 98o 40.510) - Junction of 29, 16, 71
mile 0.8 (30o 46.291; 98o 40.213) - on the left is road to abandoned granite quarry
mile 1.5 (30o 46.815; 98o 39.847) - on the right is road to, abandoned vermiculite mine
mile 2.2 (30o 47.444; 98o 39.788) - airport entrance on right
mile 4.0 (30o 48.879; 98o 39.454) - highway 215 on right
mile 8.5 (30o 52.811; 98o 39.230) - highway 226 on right, view to Babyhead Ridge
mile 9.2 (30o 53.428; 98o 39.502) - llanite granite dike - Babyhead Ridge
mile 9.5 (30o 53.602; 98o 39.608) - roadside park on left, views of llanite dike ridge to the east
mile 9.9 (30o 53.836; 98o 39.961) - outcrop
mile 13.3 (30o 56.445; 98o 41.668) - outcrop of fractured granite
mile 16.3 (30o 58.887; 98o 42.493) - town of Cherokee, intersection with highway 501
mile 17.5 (30o 59.880; 98o 42.520) - Cherokee Creek
mile 18.5 (31o 00.761; 98o 42.633) - The landscape around the town of Cherokee is open and quite flat, but look for a quarry on the west side of the road a few miles north of town (at highway 407 on right), where hard, glinty blocks of dark gray Cambrian-Ordovician limestone are about 500 million years old.
mile 21.7 (31o 03.415; 98o 43.848) - Buffalo Creek, outcrop of the Ordovician Ellenburger group . It is dense, with many chert nodules. outcrop is under the southwest corner of the bridge
mile 21.8 (31o 03.459; 98o 43.866) - limestone roadcut on right side
mile 22.1 (31o 03.673; 98o 43.898) - limestone roadcut
mile 26.7 (31o 07.432; 98o 44.382) - limestone outcrop in small creek
mile 27.8 (31o 08.448; 98o 44.038) - limestone outcrop in creek
mile 29.7 (31o 09.855; 98o 43.051) - Simpson Creek crossing, Marble Falls Limestone of Pennsylvanian age
mile 31.9 (31o 11.748; 98o 43.105) - San Saba at intersection with highway 190
There is one spot where the colorful pink, gray and black limestone is filled with fossils, that being the C.B. Lambert Ranch . The ranch is open to collecting, for a small fee, and advance arrangements can be made by writing to Mr. C.B. Lambert, Box 172, San Saba, Texas 76877. The Lamberts are rockhounds themselves and enjoy showing what they have gathered over the years.
To reach the ranch, go west from San Saba on highway 190 about 2.2 miles, turn left onto farm road 1030, and follow that road about 6.9 more miles. At that point, there will be a house and large red barn on your left. Turn, cross the cattle guard, bear to the right around the barn, and proceed about 2 more miles to the Lambert house.
A heavy-duty vehicle is desirable, since it is a rough ride to the digging area from the ranch house. The fossil-bearing ground is periodically cleaned with a bulldozer to make collecting easier, and many types of fossils can be found there.
The colorful limestone takes a good polish and can be used to produce lovely fossil-filled spheres, desk sets and bookends.