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counties, and is cut off from the Colorado district by the intervention of eminences of the older Paleozoic rocks and the Cretaceous overlap in Burnet County. These districts are all southern analogues of the belts of Indian Territory.

The southernmost area of the Carboniferous exposures in the Central Province is found in the southeastern part of the Burnet Country, southeastward of Burnet, along the Colorado, between Marble Falls and Travis Peak post-offices. This outcrop is separated from the Colorado district to the north by the Burnet granite and older Paleozoic rocks and overlap of the Cretaceous in northern Burnet County.

A good section of the typical locality of these rocks is exposed on a line along the Colorado River from Marble Falls east, the rocks dipping beneath the Cretaceous southeastward. The beds consist of about 300 feet of shaly fossiliferous limestone (the Marble Falls limestone of the writer). This occupies the stratigraphic position of, and is probably the same as, the formation of the Colorado district to which the name "Bend division" was later given by Cummins. The limestone passes upward into shales and sandstones equivalent to the basal portion of the Richmond beds of the Colorado section.

.-The basement limestone over which the river falls at Marble Falls, a short distance down the stream, rests upon the Ordovician. Its upper contact with the basal shales of the Richland division is seen in the river banks at the falls and in the bluffs of Backbone Creek in the town of Marble Falls. The lake above the natural dam of the Colorado at Marble Falls is formed by the erosion of the shales down to a floor of the shaly limestones, which here dip up the stream. This limestone outcrops elsewhere on the southern and eastern sides of the Burnet Country at various places below the Cretaceous scarp, between Colorado River and the town of Burnet. It largely forms the topographic feature in the region known as the Shinbone Ridge, extending from Marble Falls on the Colorado northward toward Burnet. Patches are found at several places elsewhere in the general Burnet district, notably near Packsaddle Mountain.

At Marble Falls and at a point about 5 miles east of that town, the lower limestones are overlain by shales and sandstones equivalent to the Richland formation of the Colorado district. The upward continuation of the Richland formation, or that portion in which we should expect to find the coal beds, is concealed in the Smithwick district by the unconformable overlap of the Cretaceous. Borings, if made in the valley of the Colorado, in western Travis County, would probably strike the buried coal beds. "

Am. Geologist, May, 1889, p. 3.

See First Ann. Rept. Geol. Survey of Texas, 1889, Pl. III.