12 ///// Paleontology of the Triiuty Division. 



II. POSITION AND CHARACTERISTICS OF THE TRINITY 



DIVISION. 



Fuller details concerning the extent and occurrence of the 

 Trinity Division have been largely set forth during the past year 

 in a publication by the writer,* and much of its stratigraphic 

 details and some of the final maps as made by him and his as- 

 sistants, Messrs. J. A. Taff, J. S. Stone, W. T. Davidson, and N. 

 F. Drake, have been printed still later. f 



The details of the formation can be appreciated by referring 

 to the published descriptions of three typical sections, made at 

 widely separated intervals, showing the increasing thickness of 

 the beds to the southward.- 



The first of these, made by the writer while employed upon 

 the work of the Arkansas State survey, is described in the report 

 upon the Neozoic geology of southwestern Arkansas. J 



The second represents the beds as they occur in the vicinity 

 of the Paluxy and Brazos rivers, in north central Texas, and 

 was made by the writer and his assistants, Messrs. J. S. Stone and 

 W. T. Davidson, and published in the report " On the Occur- 

 rence of Underground Water," and later in the Third Annual 

 Report of -the Geological Survey of Texas. || In this region the 

 beds of the Trinity Division attain an established thickness of 

 about 475 feet. 



The third and southernmost section was made along the banks 

 of the Colorado river between Austin and the Paleozoic contact 

 in Burnet county by the writer and his assistants, Messrs. J. A. 

 Taff and N. F. Drake. The rocks of the Trinity Division attain 

 unusual development in this region and are very satisfactorily 

 exposed. A profile ^] illustrating this section is published in the 



*"'On the Occurrence of Artesian and Other Underground Waters in 

 Texas, New Mexico, and Indian Territory West of the Ninety-seventh 

 Meridian" (pp. 41-106 of "Final Reports of the Artesian and Underflow 

 Investigation, etc., to the Secretary of Agriculture." 52d Congress, 1st 

 Session, Ex. Doc. 41, part 3, Washington, D. C., May, 18;)2). 



t Report on the Cretaceous Area North of the Colorado River, by J. A. 

 Taff. Austin, Texas, September, 181)2. 



tOp. cit, pp. 1 10- 12(5. 



2 Op. cit, pp. 111-112. 



|| Op. cit, pp. 307,310,311. 



If Loc. cit., pp. 90-91. 



