728 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



Pine Bluff in Jefferson County to the Louisiana line.""''*™* It is concealed in northern 

 Louisiana over a large area by the swamp deposits of Ouachita River, but again comes to the 

 surface in southern Caldwell Parish and thence occupies a belt of territory that crosses Red River 

 at Montgomery and Sabine River just below Robinson's Ferry, Sabiue 'County. 



According to A. C. Veatch*'^^ the Eocene beds, which in central Louisiana, Mississippi, and 

 Alabama are fossiliferous, all become lignitiferous in the upper portion of the embayment. The 

 marine fossils of the Wilcox, St. Maurice, and Jackson epochs each extend farther northward than 

 those of the preceding epochs, but in each case the beds bearing marine fossils grade into 

 lignitiferous clays and sands containing no distinctive marine fossils. 



Veatch says: "The first name given to this lignitiferous group, which can not be separated 

 except on structural grounds, was the Lagrange. This included all the Eocene beds in Tennessee 

 above the Midway and was afterward quite logically extended by its author. Prof. J. M. Safford, 

 State geologist of Tennessee, to include the hgnitiferous sands and clays of Crowleys Ridge," 

 which are of lower Jackson age. and are the stratigraphic equivalents of the beds in the upper 

 Chickasaw Bluffs. This formation grows more sandy to the north, where at Memphis essen- 

 tially continuous sand beds 800 feet thick have been penetrated. " * 



The following is taken from an unpublished manuscript by Deussen : 



"The Jackson formation ia eastern Texas lies stratigraphically and conformably above 

 the Yegua and beneath the Catahoula. It consists of a series of calcareous, fossUiferous clays 

 of marine origin with large limestone concretions. It outcrops in the region between Trinity 

 and Sabine rivers, in Sabiue, San Augustiae, and Angelina counties. Along the Sabiae the 

 formation is estimated to be 250 feet thick. It thins rapidly westward and disappears com- 

 pletely between Trinity and Brazos rivers. The formation is characterized by such fossils as 

 Umhrella planulata Conrad, Levifusus hranneri Harris, and Trochocyatus lunulitiformis var. 

 montgomerimsis Vaughan. 



"On Sabine River 1 mile below Robertson's Ferry, in Sabine County, highly fossiliferous 

 calcareous clays and marls carrying large limestone concretions outcrop and carry characteristic 

 Jackson fossils. The following species occur here: Mitra miUingtoni Conrad, Eipponyx ameri- 

 canus Conrad, Calyptrma trochiformis Lamarck, Ostrea trigonalis Conrad, Area (ScapTiarca) 

 rhomhoideUa Lea, Crassatellites Jlexurus Conrad, Cardium (Protocardia) nicolletti Conrad, Dione 

 securiformis Conrad, Corhula wailesiana Harris. 



"The Jackson formation extends from Angelina River in Texas eastward across Louisiana 

 into Mississippi. In Texas the time equivalents of the formation have been traced as far west 

 as the Brazos. The equivalents iu the region of the Brazos, however, are not lithologicaUy 

 similar to the Jackson formation and therefore do not belong to the Jackson but are here a part 

 of the lithologic unit next to be described, namely, the Catahoula sandstone." 



The Jackson has not been recognized in southwestern Texas, although more thorough 

 investigation may discover it in that region. 



OLIGOCENE. 



Vicksburg limestone. — This formation is known west of Mississippi River only in a small 

 area in northern Catahoula Parish, La. The material is yellow calcareous clay and yellow 

 limestone, which contains typical fossils. *="' 



In Louisiana and eastern Texas the Oligocene deposits are divided into two formations — 

 a lower one, the Catahoula sandstone, which in east-central Texas also comprises the upper- 

 most Eocene and which consists of semiquartzitic sandstones and sands with some clay and 

 carries a few plant remains, and an upper one, the Fleming clay, which consists of calcareous 

 clays with nodules of lime and occasional crystals of gypsum. 



^ Report of John Lundie on waterworks system of Memphis, Tenn., 1896, p. 16. 



6 Safford, J. M., Bull. State Board of Health, vol. 5, pt. 7, Feb. 20, 1890, pp. 98-106; Ann. Kept. Geol. Survey 

 Arkansas for 1889, vol. 2, 1891, pp. 28-29. 



