610 W. T. LEE STRATIGRAPHY OF COAL FIELDS OF NEW MEXICO 



may include more than one formation, bnt it has not been studied with 

 a view to subdividing it into formations or of making exact correlations 

 with formations of other fields. These rocks are the so-called '^Creta- 

 ceous red beds" of the Cerillos region, which some geologists have corre- 

 lated with the Denver formation. Hay den (19), who named this forma- 

 tion, regarded it as Tertiary and correlated it with the Monument Creek 

 of the Denver region, the lower part of which has recently been named 

 the Dawson arkose (122) and correlated with the Arapahoe and Denver 

 formations. J. J. Stevenson (53) failed to separate the Galisteo from 

 the underlying coal measures and referred both formations to the Lara- 

 mie. D. W. Jolinson (83) also failed to recognize the unconformity at 

 the base and included the lower part of the Galisteo sandstone in his 

 Madrid group, which he referred to the Fox Hills. He referred the 

 upper part to the Laramie. Xothing lias been found in the Galisteo to 

 establish its geologic age. It contains great numbers of petrified logs, 

 which are beautifully j^reserved in external form, but the cellular struc- 

 ture of the wood is not well preserved and no specific identifications have 

 been made. The best known locality at which these logs occur is a few 

 miles east of Cerrillos, in the so-called petrified forest, where there are 

 many logs 25 to 75 feet or more in length. But logs have been found in 

 this formation in many other places in a state of preservation much better 

 than that of the logs near Cerrillos. Fossil leaves have also been found 

 in a few places, but^ their preservation is poor and few have been spe- 

 cifically identified. All things considered, it is probable that the Galisteo 

 sandstone should be correlated with those Tertiary formations farther 

 west that are similar to it in character and stratigi'aphic position. This 

 relation is indicated by the correlation lines in figure 2, page 597. 



CORBELATION WITH THE EatON SeCTION" 



The Raton coal field is located in northern ^N^ ew Mexico, east of the 

 Eocky Mountains, and is separated from the San Juan Basin by a moun- 

 tainous area about 90 miles wide. The Cretaceous and vounger forma- 

 tions of this field were described three years ago by the writer (111) as 

 consisting of Dakota sandstone, a shale equivalent in age to Benton, 

 Niobrara, and Pierre; the Trinidad sandstone, a coal-bearing formation 

 called "Laramie or older (?)," and a younger coal-bearing formation of 

 post-Laramie age lying unconformably on the older one. ITp to that 

 time these coal-bearing formations had been grouped together under the 

 name Laramie. Two years later the writer (119) traced them around 

 the Raton and Trinidad coal fields and found them unconformable in all 

 parts of the Raton Mesa region. During the later investigation a large 



