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It is an interesting fact that as these sands turn eastward down Red River their upper beds begin to encroach upon the stratigraphic position of the Walnut formation at the base of the Fredericksburg division. On both sides of Red River adjacent to Jimtown the upper limit of the sands passes into an impure sandy clay beneath the Goodland limestone, marked by the characteristic Exogyra texana fauna of the Walnut clays to the south. The same condition is seen in the bluff of Hickory Creek north of Marietta, Indian Territory.

There has been little study of the details of the Basement sands in Indian Territory. The writer has observed them only in rapid reconnaissances and noted points here and there along the boundaries of their outcrop. In general the formation, as in Texas, consists of loose, unconsolidated sands of undetermined thickness, with occasional laminae of clay. The subsoil is usually red, from the oxidation of the contained iron, and the soil a leached, ashen gray.

From Healdton eastward to the Arkansas line they are better displayed and exhibit the general surface characters exposed in Texas. Débris of the Permian conglomerates also occurs between Trinity River and Woodford, Indian Territory, and Silurian limestone pebbles occur southwest of Ardmore. For a short distance between Tishomingo and Boggy Depot, Indian Territory, debris of granites and Paleozoic limestones is found in the Basement sands. Elsewhere the beds are composed of débris of the Carboniferous sandstones.

From Powell's crossing of the Brazos, west of north from Anthon and Whitt, in the northwest corner of Parker County, are excellent exposures of the Basement sands in contact with the Underlying Carboniferous; good general sections of the entire Trinity division from the base of the Fredericksburg, which forms the escarpment of the Grand Prairie, are procurable.

The Basement sands, as noted by Taff, occur in good exposures along a run three-fourths of a mile southeast of Hiner just north of the Brazos. They