580 W. T. LEE STRATIGRAPHY OF COAL FIELDS OF NEW MEXICO ' 



beds of all these fields were of practically the same age, so that when 

 those of the more northerly fields Avere called Laramie it was quite nat- 

 ural that Stevenson should extend the name to the Cerrillos field without 

 presenting as clear evidence of age as could be desired. Thus, while 

 Stevenson correlated the coal beds of the Cerrillos field with the so-called 

 Laramie farther north, he held that the Laramie was Cretaceous. In 

 other words, his Laramie was equivalent to the upper part of Hayden's 

 Fox Hills group. In 1881 (52 and 53) the full account of Stevenson's 

 investigation appeared, and although the coal beds are referred definitely 

 to the Laramie, a step was taken toward their j^resent reference to the 

 Mesaverde when he reported (52, page 371) the occurrence of marine 

 and brackish water fossils from "high up in the Laramie." It should be 

 noted in passing that Stevenson's "Laramie" included not only the coal- 

 bearing rocks, but many, if not all, of the younger rocks that other 

 writers have described as Galisteo. The descriptions in his several papers 

 on the Galisteo region, his maps of the region (54, number 77 (B), and 

 number 78 (A)), and his cross-section (52 and 53, page 341, figure 49) 

 leaeve no room for doubt that his "Laramie" includes the rocks of both 

 the Mesaverde and the Galisteo formations of the present paper. 



For several years after Stevenson's investigation little new informa- 

 tion was gained concerning the coal measures of central and western Xew 

 Mexico, but several more or less definite references to them are found in 

 the literature. Cope, who was interested in the Tertiary vertebrates of 

 northwestern New Mexico, makes mention of the underlying coal beds 

 (55), which he refers, in part at least, to the Laramie. The coal beds of 

 Gallinas Mountains are shown as occurring below "Fox Hills" (57), and 

 the Puerco and Laramie are included under "post-Cretaceous," although 

 Cope explains in the text that the Puerco belongs in the "Tertiary rather 

 than the post-Cretaceous." 



Little work was done on the coal-bearing rocks of New Mexico during 

 the nineties, although Stevenson (69) visited the Cerrillos coal field 

 again in 1896 and added a little to the information that he had already 

 given. However, observations were being made by Cross, Spencer, and 

 others in southwestern Colorado that were destined to have a notable 

 influence on the investigations of the New Mexico coal-bearing rocks. 

 In 1898 Spencer (73) announced that rocks of Benton, Niobrara, and 

 Pierre age in southwestern Colorado are not divisible on lithologic 

 grounds, and that massive sandstones occur higher in the section which 

 might prove to contain equivalents of both Fox Hills and Laramie. This 

 was followed a year later (75) by the La Plata folio, in which Cross 

 names the coal-bearing rocks Mesaverde, the shale between them and the 



