B18 ^y. t. lee — stratigraphy of coal fields of kew Mexico 



and character within short distances rests unconformably on the coal- 

 bearing rocks. For about 75 feet above this basai conglomerate the rock 

 is variable in lithologic character and consists of friable, granular sand- 

 stone and shale, irregularly intermingled, and in it are many lenses and 

 irregular masses of conglomerate. The whole mass is dark colored and 

 gives the impression of being the erosional product of a mass of dark- 

 colored igneous rock. The suggestion is offered that this formation may 

 represent the Animas formation of the Durango region, although its 

 stratigraphic position would tend to make it somewhat older than the 

 Animas. 



Section of Rocks measured about one Mile Noi'thicest of Diilce, Xew Mexico 



Feet 



Sandstone, conglomeratic, brown 80+ 



Sandstone, slightly sbaly, with greenish tint at base ; massive, yellow 



above 44 



Shale and sandstone, yellow 121 



Sandstone, shaly, greenish 6 



Conglomerate with pebbles, principally of chert, up to one-half inch 



in diameter 12 



Sandstone, shaly, gray 27 



Ck)nglomerate with chert pebbles up to three-quarters inch in diameter 28 



Shale, sandy, yellow 8 



Sandstone, white 3 



Shale, sandy, yellow 10 



Conglomerate with chert pebbles up to three-quarters inch in diameter 38 



Shale, sandy, yellow 18 



Sandstone, massive, coarse-grained, yellow 66 



Shale, sandy, dark-colored 21 



Sandstone, friable, dark-colored 46 



Sandstone, coarse-grained, conglomeratic, with pebbles mostly of chert 



up to an inch or more in diameter 6 



(Unconformity by erosion.) 



Shale, sandy, carbonaceous ; contains fossil leaves ( U. S. G- S. locality 



No. 6042) 83 



Coal, coke, and intruded igneous rock 8 



Sandstone, coarse-grained, light-colored 66 



Shale, sandy 8 



Sandstone, massive, light-colored 60 



Shale (Lewis), fossiliferous (U. S. G. S. locality Nos. 7200 and 7201) . 300+ 



Total 1,059 



The writer found no fossils in rocks above the unconformity, but other 

 geologists seem to have been more fortunate. J. H. Gardner, who is 

 familiar with this region, has, at the writer's request, furnished the fol- 

 lowing information in a letter dated December 26, 1911: 



