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of undetermined Cerithiidae, Neritina, Ostrea, Aguillaria cumminsi (White), and other littoral species. From a well at Whitesboro, which was dug in the sharp sands of this division, I procured fish teeth (Otodus), an Ammonite (Scaphites), and indeterminate mollusks.

In the vicinity of Red River these sands are covered by a Post-Tertiary sand, which confuses their identity there. South of the Brazos and at Austin these beds are entirely missing, a fact which is explicable in connection with certain volcanic events which took place just after they were laid down, exposing them to denudation before the next division was deposited.

No systematic study of these beds, as a whole, has yet been made, and the thickness is estimated from casual observations by the writer. There is no more inviting field in Texas for study than these beds. Dr. B. F. Shumard discovered dicotyledonous leaves in this formation, and reported the same in the proceedings of the St. Louis Academy of Science, vol. 2, p. 140. He also correlated these sands with the Dakota group, or No. 1 of Meek and Hayden's section. They are probably the same as the Arenaceous group of Shumard's Texas section.

Beneath the scarp of the white rock (Austin chalk) at Dallas, and extending westward through the "Mountain Creek country" to the Lower Cross Timbers, can be seen the clays of this division of the Upper series, the thickness of which I place at 400 feet as a low estimate. These clays in their medial portion are dark blue and shaly, highly laminated, and occasionally accompanied by gigantic "cannon ball" nodular septariæ. Their lower contact with the Cross Timber sands has not been seen by the writer, nor recorded to his knowledge. The uppermost beds gradually become more calcareous, gradating rather sharply into the chalk. At Austin these beds occur in the same relative position, but are of varying thickness, and at one place—where Tenth Street crosses Shoal Creek—they are missing, the chalk resting on the Shoal Creek limestone. The northwestern part of the city is underlaid by these clays, which are here more calcareous, and accompanied by thin bands of laminated limestone. South of the river, along the International Railroad, they are finely displayed in Bouldin's Creek, with the characteristic blue color on fresh exposure.

They also appear at San Antonio near the cement works there, and probably occur at many intermediate points. North of Waco they increase in extent and thickness, forming extensive black waxy areas in Hill, Johnson, and Dallas counties, west of the white rock scarp. I have proposed for these areas the name Minor Black Waxy Areas, to distinguish them from the main Black Prairie Area underlaid by the Ponderosa marls.