DESCRIPTIVE DETAILS I CERRILLOS FIELD 645 



Feet Inches 



Sandstone and shale 5 



Sandstone 16 



Shale 8 



Coal 11 



Shale 9 



Coal 8 



Shale 16 



191 9 



Few fossils were found in the coal-bearing rocks at Madrid, although 

 careful search Avas made for them. The shale beds overlying the coal in 

 the mines near Madrid were searched, but at only one locality were fossil 

 plants found in them. This is about a mile south of Madrid in the roof 

 of a prospect opening in the White Ash coal bed, where conifers, identi- 

 fied as probably belonging to the genus Geinitzia, were found in shale 

 above the coal. Where the Cook and White bed crosses Coal Gulch north 

 of Madrid this coal bed is overlain by a massive sandstone in which are 

 pinkish brown concretions of sandstone. In one of these concretions 

 were found impressions of shells similar in appearance to some of the 

 shells of marine origin that occur so abundantly in the sandstones at the 

 base of the Mesaverde. The writer found no other shells above the coal 

 beds near Madrid, but J. J. Stevenson (53, page 155) reports the occur- 

 rence of Inoceramus and Ostrea in the coal-bearing rocks. 



The rocks at Madrid dip east about 15 degrees, and the mine entries 

 have been driven down this dip under an intrusive sheet of igneous rock 

 which forms the crest of a hill east of the town. Above this sheet and 

 in a gulch about half a mile east of Madrid coal-bearing rocks are ex- 

 posed near the mouth of an abandoned mine. The following section was 

 measured by D. W. Johnson (83, page 107) at this locality and the sec- 

 tion was later confirmed by the present writer. To the fossil plants 

 reported by Doctor Johnson have been added those collected by the 

 writer. 



Section of Rocks measured at an abandoned Coal Mine one-half Mile Ea^t of 



Madrid, 'New Mexico 



Feet 



Loose sand, upper part concealed 



Intruded lava sheet 1 



Sandstone, soft 8 



Intruded lava sheet 3 



Sandstone, soft 10 



Sandstone^ indurated, containina: Ficus rhamnoides Kn. ; Ficus vncata 

 Lesq. ; Ficus speciosissima 1 Ward ; Ficus sp, type F. planicostata 

 Lesq. ; Palniocarpnn commune ? Lesq.; Gronomitcs sp. ; Qucrcus ? sp. ; 

 Aralia 1 sp. ; (U. S. G- S. locality No. 6019) 9 



