Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/303

Rh and as the roof of all these old pits is very soft and treacherous, it renders mining at this point very expensive, as it necessitates an ever increasing amount of stripping as the operations are advanced. Several of the cuts are 30′ to 40′ wide and over 100′ in length, and even if the deposits have been pretty generally exhausted the dimensions of these openings would seem to indicate the fact that they had furnished a large quantity of wash-ore in the past. This fact is the more important, as the McGurk deposits seem to be the only occurrence of iron-ore at this horizon upon a commercial scale so far found in the district; for though these central sandstone ridges give evidence of many similar outcrops, none of them have ever proved worthy of development, either by reason of the chemical quality of the ore found in the test pits or of the quantity collected at any one point. Other deposits of iron ore have been found in these ridges, but they all seem to be associated with the bottom layers of the Marcellus slate formation, overlying the sandstone rather than underlying it, as seems to be the case at the McGurk bank.

The Moore ore bank, an old opening situated about 3 miles northwest of Lewistown, in the south dip of the Marcellus slate and limestone and in the Squaw Hollow synclinal, is one of these ore deposits which seems to be more closely associated with No. VIII than No. VII. It was opened by the Logan I. & S. Co. in 1871 and though abandoned now, it furnished quite a large quantity of brown hematite ore from the surface to a depth of 80′, no carbonate ore having been met with. The following analysis (McCreath) shows the character of this ore:

Like the Townsend bed, situated in a similar geological position in the No. VIII slates of Derry township, this ore bed was of varying thickness, with an average somewhere