NORTH AMERICA AND THEIR VERTEBRATE FAUNA. II 



the red being predominant, with an occasional bed of darlv earthy limestone con- 

 taining usually an abundance of poorly preserved fossils. 



"At the Bar-X Ranch on the Wichita River, in the northeast comer of Baylor 

 County, near the Old Military Crossing, several ledges of hard limestone appear 

 in the river bluffs, separated by varying thicknesses of blue shale, alternating with 

 red clay. The beds dip to the westward at inclinations estimated at 20 to 30 feet 

 per mile. Proceeding up the river from this point, limestones appear at intervals 

 in increasing development, the best outcrops occurring about 2 miles east of where 

 the Seymour- Vernon road crosses the river. Here an escarpment 90 feet in height 

 has the lower two-thirds composed of red and blue shales alternating with beds 

 of limestone. The middle of the section consists of red and concretionary clays 

 and sandstones. Some of the ledges of limestone are massive, but others are 

 thin-bedded and shaly, and separated by varying thicknesses of bluish clay. Locally 

 the thin-bedded limestones and their included shale grade horizontally into more 

 massivel}' bedded limestones. Fossils are not plentiful in this locality. The same 

 beds are exposed again northward in the banks of Beaver Creek. At Seymour 

 the limestones are well exposed in the banks of the river, where they are quarried 

 to some extent and furnish a stone that is well adapted to ordinary uses. The beds 

 are here transected by the Salt Fork of the Brazos, which flows in a relatively 

 narrow valley between steep bluffs 200 feet high, made up of interbedded red and 

 blue clays and limestones. 



"The limestones of Baylor County area are generally fossiliferous. Owing 

 to the hardness of the rock, however, good specimens are difficult to obtain. Toward 

 the south there is an increase in the development of blue shale and limestone, while 

 the red clays and sands show a corresponding diminution. * * * " 



"That the limestone series of Baylor County is the equivalent of the 'Albany' 

 formation of the southern area is fully established by both the stratigraphic and 

 the faunal evidence. The beds in the northern area, which include the limestones, 

 shales, and sandstones of Baylor County and the sandstones and shales of Archer 

 and Wichita Counties, constitute the Wichita formation" (p. 122). 



In a later paper Gordon" gave the following account of the Wichita: 



"The Wichita formation underlies practically the whole of Wichita, Baylor, 

 Throckmorton, and Shackelford Counties, a considerable part of Clay and Archer 

 Counties, and a small part of Young County. In Shackelford County it consists 

 of blue clays and shales with thick beds of limestones which, on account of their 

 greater resistance to erosion, crop out in a series of eastward-facing rock scarps. 

 The limestones, which constitute about a third of the formation, are blue, gray, 

 and yellowish, and for the most part massively bedded. They are generally hard, 

 semicrystalline to compact, but some beds are friable and chalky and others are 

 rough and earthy in texture. Thick beds and thin and shaly beds alternate. The 

 remainder of the formation consists of blue, gray, and black shales. The hmestones 

 contain an abundance of marine fossils, but well-preserved specimens are difficult 

 to obtain. 



"Farther north there is a marked diminution in the proportion of calcareous 

 sediments, with a corresponding increa.se in argillaceous and arenaceous materials. 

 Some of the clay beds in Shackelford County are sandy, but toward the north the 

 sandy sediments become more and more prominent, many of the layers taking 

 on a red color. Red, white, and yellowish sandstone beds also make their appear- 



" Gordon, U. S. Geological Survey, Water Supply and Irrigation Paper No. 317, 1913, p. 22. 



