8o Bulletin 15 390 



In 1895, Ml"- William Kennedy* referred both the Fayette 

 sandstones and the Frio clays to the lower Claiborne, because of 

 the presence of Venericardia planicosta in the sandstones. Mr. 

 Veatch, during the winter of 1902, has examined the sandstones 

 and finds Venericardia planicosta is limited to the basal layers of 

 the formation. These he refers to the Jackson; but the greater 

 portion of the sandstones and the lower beds of the Frio clays he 

 regards as Grand Gulf. 



The sandstones are often cross-bedded and lenticular. Clays 

 predominate in the upper part of the series. 



Flora and fau7ia of Grand Gulf beds. The Grand Gulf beds 

 contain abundant remains of palmetto, rushes, marsh grass and 

 and other vegetation of a marshy habitat. The upper clays of the 

 series are characfterized by tree trunks which have become opalized 

 by the infiltration of silex. There appear to be no indigenous 

 animal remains, but a few have been reported washed in from 

 neighboring beds. 



The Frio clays. The Frio clays are a series of dark blue, red, 

 green, brown and yellow clays, weathering to paler colors. The 

 beds are more or less gypseous throughout. They are sometimes 

 laminated, but usually massive. They overlie the Grand Gulf 

 beds, and form a belt of nearly equal width. Mr. Kennedyf writes 

 that they extend almost to the Louisiana line; but Mr. Veatch has 

 shov/n that they continue for some distance into the state. 



Fossiliferous bed in Frio clays near Burkville. The Frio clays 

 have been thought to be fossiliferous only in central and western 

 Texas, but Mr. Veatch found a fossiliferous layer near Burkville, 

 not far from the eastern state line. The bed was about 100 feet 

 above the base of the clays. The fossils are all in the form of casts. 

 The matrix is a peculiar ferruginous rock, loosely consolidated and 

 containing siliceous nodules with a geoditic stru(5ture. The fauna 

 appears to be brackish. 



Correlation of the Oligocene beds in the Southern States. A 

 correlation of the Oligocene beds discussed in the preceding pages 

 is given in the following table: 



* Eocene Tertiary of Texas, Proc. Acad. Nat. Sci., Phila., 1895, pp. 92, 98. 

 ■f/did., p. 94. 



