B. T. Hill — The alleged Jurassic of Texas. 453 



tematic observations on the stratigraphy of these formations, 

 written by me, and, at my request, by Messrs. Stanton and 

 Vaughan, can be found in this Journal from 1877 to the present 

 year, in the papers to be enumerated presently. Within the 

 past few years I have paid special attention to these isolated 

 but related localities in Kansas, New Mexico and Trans Pecos, 

 Texas, and their relations to the Central Texas region where 

 the main area of the Cretaceous lies in continuous section. 

 The three papers specially showing the identity of Professor 

 Marcou's Jurassic of New Mexico with the beds of the Washita 

 Division in Texas, are entitled " Outlying Areas of the 

 Comanche Series in Kansas, Oklahoma and New Mexico," 

 with ex parte paleontologic determinations by T. W. Stanton 

 and F. H. Knowlton, published in this Journal of September, 

 1895 ; " Section of the Cretaceous at El Paso, Texas," by T. 

 W. Stanton and T. Wayland Vaughan, this Journal, vol. i, p. 

 21, 1896; and Additional Notes on the Outlying Areas of the 

 Comanche Series in Oklahoma and Kansas" by T. Wayland 

 Yaughan, this Journal, July, 1897. These three papers cover 

 every well known essential point concerning these regions and 

 should be read by all who wish to know the true merits of 

 Professor Marcou's determinations of the localities discussed. 



Furthermore, two previous bulletins of the Geological 

 Society of America,* written by me upon the paleontologic 

 and stratigraphic relations of the Cretaceous formations of 

 Indian Territory and Texas adjacent to Red River — the locali- 

 ties from which the Cretaceous fossils described by Professor 

 Marcou, in his Geology of North America, were collected — 

 set forth the details of the comprehensive section of the Cre- 

 taceous developed in that region by which the stratigraphic 

 position of Professor Marcou's isolated outcrops can be located 

 in the general section. Finally, concerning the paleontology 

 of the entirely distinct Trinity Division as published in my 

 Arkansas Report — the only one of my papers to which Pro- 

 fessor Marcou refers, — I will state that the paleontologic 

 descriptions and figures of that volume were fully revised and 

 republished by me in a paper entitled "The Invertebrate 

 Paleontology of the Trinity Division," published in the Pro- 

 ceedings of the Biological Society of Washington, vol. viii, pp. 

 9-40, Plates I- VIII, June 3, 1893, and that this later paper, 

 not the Arkansas Report, represents my views of the fauna 

 discussed. In this later paper the description of the form 

 from Arkansas described by me under the name of Ammonites 

 walcotti, is fully revised by Professor Hyatt and redescribed 

 by me, and my previous generic and specific comparisons as 

 quoted by Marcou (p. 199)f are abandoned and superseded. 



* Vol. ii, pp. 503-528, 1891, and vol. v. pp. 297-338, 1894. 

 f This Journal, Sept., 1897. 



