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



A comparison of this section witli the 1,602-foot drill record seems to 

 show that the lowest bed of coal, which is only 4 inches tliick where the 

 section was measured, but which is somewhat thicker in other places, 

 corresponds in stratigraphic position with the lowest coal beds represented 

 in that record; that the 100-foot sandstone of this section finds its coun- 

 terpart in the 169-foot sandstone of the drill record, and that the coal 

 developed in the Omera mine corresponds in position with the middle 

 group of coal beds of the drill record and with the lowest developed coal 

 of the Eogers section (see figure 5). If this correlation is correct it is 

 evident that a large part of the Mesaverde formation as represented in 

 other parts of the Cerrillos coal field is not present at Omera, and that 

 the unconformity above the Omera coal represents an erosion interval of 

 long duration. 



As indicated in the foregoing section, the conglomerate of the Galisteo 

 sandstone rests in some places directly on a coal bed. This bed varies 

 considerably in thickness within short distances. In some places where 

 shale intervenes between the coal and the overlying conglomeratic sand- 

 stone the coal bed is 4 to 5 feet thick. In other places where the con- 

 glomeratic sandstone rests on it the coal is thinner and in some localities 

 is entirely replaced by the sandstone. This was found to be the case in 

 the mine workings. J. H. Gardner states in his unjDublished notes of the 

 Omera mine that 560 feet down an old slope the coal suddenly disappears 

 against a face of sandstone showing no evidence of faulting. He found 

 that this disappearance was due to total erosion of the coal bed previous 

 to the deposition of the sandstone. He also states that at one locality 

 near Omera mine he found two coal beds separated by 9 feet of sandstone, 

 the lower one 3 feet thick and the upper one 4 feet 6 inches thick. At 

 one of the prospect entries, a few rods from the place where the Omera 

 mine section given above was measured, the present writer observed two 

 coal beds as follows: 



Section of RocJiS measured near Omera Mine 



Feet Inches 

 Conglomerate with pebbles of several kinds of rock, including an- 

 gular fragments of coal 



Coal 2 



Shale, sandy 2 6 



Coal 4 2 



Shale 



6 10 



