434: C. A. White — ^Relation of the Laramie Group 



While I have no doubt as to the Laramie age of the strata 

 referred to, which I observed on both sides of the Rio Grande, 

 and none as to the Eocene age of the strata which I found 

 overlying them, I am by no means certain that the lowermost 

 strata which I found resting upon the Laramie near Laredo 

 represent the lowermost strata of the Eocene division of the 

 Gulf series. Indeed, so far as I could discover, no equivalent 

 of the " Northern Lignite " the lowermost member of the 

 Eocene of Hilgard's Mississippi section, exists in the region 

 round about Laredo, unless the coal-bearing strata of the upper 

 portion of the Laramie are really its equivalent. I am dis- 

 posed to accept this view of the case, and to regard the 

 Northern Lignite of the Mississippi section and its equivalents 

 elsewhere, including the uppermost strata of the Laramie, as 

 really of Eocene age. 



Those lignitic beds in the State of Mississippi and in eastern 

 Texas rest directly upon the Ripley Group, the uppermost of 

 the marine Cretaceous series of the Gulf region, just as the 

 Laramie rests upon the equivalent of the Fox Hills and Ripley 

 Groups in western Texas. But the faunal hiatus between the 

 Ripley and marine Eocene beds in those eastern regions is so 

 great that one may reasonably suppose it to represent sufficient 

 time for the deposition of a larger and more important forma- 

 tion than the lignitic beds alone constitute there ; such a 

 formation, for example, as is the Laramie Group. Still, the 

 fact remains that the Laramie Group as a whole is, in the val- 

 ley of the lower Rio Grande, overlaid by strata which all agree 

 to be of Eocene age. This fact makes it certain that the Lara- 

 mie Group as a whole is older than certain well marked Eocene 

 strata ; and it is also presumptive evidence of the Cretaceous 

 age of at least the greater part of the Laramie. There are 

 also other facts pointing to the same conclusion which will be 

 discussed in the following paragraphs. 



Several years ago, Dr. G. M. Dawson announced the exist- 

 ence, in that portion of British America which is in large part 

 drained by the Saskatchewan River and its tributaries, of a 

 formation in the Cretaceous series which had not before been 

 recognized, and to which he gave the name of " Belly River 

 series." Since then both he and other members of the Cana- 

 dian Geological Survey have from time to time published 

 accounts of the same formation.* They report this formation 

 as resting upon the equivalent of the combined Benton and 

 Niobrara groups of Meek & Hayden's section of the Upper 



*See Dawson, Geo. M., Geol. and Nat. Hist. Survey Canada for 1882-83-84. 

 C. pp. 1-169. Dawson, Geo. M., ib. for 1885, B. p. 16C. McOonnell, R. G., ib. 

 for 1885, C. pp. 1^85. Whiteaves, J. F., Contributions to Canadian Paleontology, 

 vol. i, Part I, 1885. 



