Chemical analyses show that a reef approximately 100 feet thick in the lower portionof the Marble Falls limestone near Marble Falls, Burnet County, Texas, is exceptionally pure. Only the Honeycut formation, of the other formations described, contains limestone that might be of value.The type section of the Marble Falls limestone is described, including thin-section and insoluble residue descriptions.

Palo Alto Creek quadrangle is south of the Llano region and is in the marginal portion of the Edwards Plateau where much of the plateau surface has been destroyed by erosion. Along the northern edge of the quadrangle, a portion of a finger of the plateau trends eastward, and in the west-central part, another finger of the plateau frays out into a number of isolated outliers. The rest of the quadrangle is a portion of the gently undulating broad Pedernales River basin.