coal. 3B7 



THE CA.VFIELD-ERIB DISTRICT. 



The western and northern limits of the Canfield-Erie districl are the 

 outcrop of the measures beneath the Quaternary of the Boulder Valley, 

 contracted somewhal by the natural deterioration of the coal under decrease 

 of cover, and perhaps also, at the northern end, by a thinning of the coal 

 below workable thickness. The eastern limit of the field lies ;i few 

 hundred feet west of the lower Coal Creek fault; the southern, a little 

 north of the Erie fracture, the beds on this side of it being turned up 

 against the plane. Near the western edge of the area, where this fault 

 has apparently disappeared, the Canfield-Erie and .Mitchell Gelds become 

 continuous. 



The disturbed condition of the strata in proximity to the faults has 

 been noted in the preceding pages. In this portion of the district the 

 measures lie in the gentlest possible curve consistent with a synclinal 

 structure, approximating the horizontal over much of the area. Local 



flexures occur, and also faults of small throw. Of the latter the Jackson- 

 Star is the most important thus far encountered. The throw is hut 30 feet, 

 however, not enough to have exposed any of the beds to the influence of 

 erosion and so brought about their removal. 



The stratigraphy of the Canfield-Erie region is somewhat less clearly 

 defined than that of the .Mitchell, chiefly because of the less satisfactory 

 data afforded by the mines. The succession of strata in the Progress shaft 

 (PI. KVII) and in another prospect a short distance from this indicates that 

 the seam worked in the former is the No. '_', or that above sandstone 1!. 



No reliable section of either the Star or Jackson shafts is attainable, from 

 the depth of the Star, which is about that of the Progress shaft, it is 



probable that the same bed (No. 2) is worked in both. From the depth of 



the Jackson shaft, the difference in altitude between its collar and that 

 of the Progress, and the dip of the beds in the latter mine, it is probable 

 that the seam worked in the Jackson is likewise the No. '_'. Whether the 

 No. •_' or No. 1, could readily he decided by boring or by an examination 



of the strata in the shaft. In the old Moulder Valley mine. also, the seam 

 worked was probably the No. 2. 



The new Boulder Valley mine is located on the eastern edge of this 



