Veatch — Definition of the Geologic Term, Laramie. 21 



the beds between the Wasatch and the marine Montana Creta- 

 ceous and has been most commonly and extensively used in 

 this broad sense, has led to the suggestion that the retention of 

 the name in this original sense will cause the least confusion 

 and that it therefore might be expedient to define the Laramie 

 as that series of beds occurring between the marine Montana 

 Cretaceous and the Fort Union. 



In connection with this suggestion of expediency, it should 

 be pointed out that the continued use of this term in the 

 " catch all " sense is wholly at variance with the abundance of 

 strong and wholly logical reasons for the restriction of the 

 term Laramie to the "Upper Laramie " shown by a careful 

 consideration of the historical data. If the point of confusion 

 is regarded as one of great importance, it might be worth while 

 considering the entire abandonment of the term Laramie. 



In either case a new name is required for the beds here re- 

 ferred to as " Lower Laramie." Many considerations suggest 

 that this name should come from the region of the Laramie 

 Plains. This would be historically appropriate in many ways, 

 and would result in placing the type localities of the upper and. 

 lower portions of the beds which have been called Laramie in the 

 broad sense in the same section. There are reasons for believ- 

 ing that the enormous development of Lower Laramie beds in 

 the western part of the Laramie Plains near the mouth of the 

 Medicine Bow River, or, as it is more commonly called by the 

 local people, " The Bow," where there is relatively very little 

 evidence of a break between the upper and lower beds, more 

 completely represents the Laramie deposition than at any other 

 point. These considerations make the Bow formation or group 

 a very appropriate designation for these lower beds. On the 

 other hand, the fact that the region of Golden has been made 

 classic, in connection with the " Laramie problem," by the 

 studies of Cross, Eldridge, Knowlton, and others, raises the 

 question whether the name Golden formation or group might 

 not be a more appropriate name. 



The discovery of this great unconformity at all points that 

 have been critically examined over an area 1,000 miles north 

 and south and 250 miles east and west, the fact that it occurs 

 on both the east and west sides of the Front Range of the 

 Rocky Mountains, and its" great magnitude, all make it one of 

 the important mile-posts in the geologic history of western 

 North America. All these considerations suggest anew the 

 first conclusion of Cross in the Denver region that this uncon- 

 formity marks the dividing line between the Cretaceous and 

 Eocene in this region. On this basis the arrangement of 

 groups immedately above and below the great break would be 

 as follows : 



