108 PROCEEDINGS OF THE ACADEMY OF [1895. 



With the exception of the lignite and characteristic Jackson fossils 

 this description would answer the Texas Frio clays as well as the 

 Yegua clays. Besides their contact with and underlying the 

 Neocene Navasota beds (Oakville beds) would in the absence of the 

 Vicksburg deposits closely correspond with the Frio clays. Their 

 extension to Sabine Town, however, where they would meet the 

 Marine beds of the Texas section would naturally lead to the in- 

 ference that both the Fayette sands and Yegua clays are absent in 

 Louisiana. 



This interpretation of the work done in Louisiana can hardly be 

 accepted, and until more information is obtainable the correlation of 

 the beds in these States must be left as an unsolved problem. 



Marine Beds. 



Lying immediately north of the Yegua clays we have an extensive 

 series of green sands, green sand marls, altered green sands contain- 

 ing thin strata of carbonate of iron, indurated altered fossiliferous 

 greed sand, green fossiliferous clays, glauconitic sandstones and clays 

 stratified, black and gray sandy clays, black and yellow clays with 

 limy concretions, brown and yellow fossiliferous sands with occasional 

 deposits of black sand containing gypsum crystals, and at wide in- 

 tervals small deposits or thin seams of lignite. Extensive deposits 

 of ferruginous sandstone and limonite, both in laminated and nodular 

 form, occur in the upper divisions. The prevailing deposits, however, 

 are the green sands in their several characters. The clays are of 

 minor importance and exist generally as thin beds of irregular dis- 

 tribution interstratified with the sands. The lignites are usually not 

 more than a few inches thick and are never continuous, and the 

 limonite deposits occur as nodular ores lying in heaps or mounds 

 among the grayish- brown and gray sands or as laminated ores cover- 

 ing wide areas of the surface, particularly throughout Cherokee, 

 Anderson, and Rusk Counties. These are the iron-ore fields of 

 East Texas, and constitute the series of beds known as the Marine 

 beds of the Texas section and have a total thickness of 650-700 feet. 



Stratigraphically these beds occupy a position intermediate between 

 the overlying Yegua clays and the lignitic stage, and form the upper- 

 most division of Penrose's timber belt or Sabine River beds. :i9 In 

 the reports of the Texas Geological Survey these beds have been 



;,J First Annual Report Geol. Survey of Texas, 1889, pp. 22-47. 



