Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/331

Rh about one-half mile northeast from the railroad. It is only important as affording testimony of the structure of this high anticlinal ridge as it shows satisfactory dips of from 40° to 45° towards the southeast on the south flank of the hill.

The Enterprise Sand Co.’s quarry at Vineyard station is opened in the north leg of the synclinal south of this Chestnut Ridge axis, the south or north dipping leg of the synclinal having been eroded at this point. This is one of the newest operations in the district and is excellently equipped for an economical development of the sand bed. The Pennsylvania railroad which practically follows the south bank of the Juniata river all the way from Granville to Ryde station, crosses the river just east of Vineyard station and thereby passes immediately by the washers of the Enterprise Sand Co. greatly to their advantage. In June 1888 this company’s operation presented an extremely interesting appearance, and much surprise had been expressed at the absence of all northwest-dipping sand rocks, although apparently opened close to the north outcrop of the Lewistown limestone; but as I have already suggested, all the south leg of the synclinal has been eroded down to the water level, which is the reason why there is but a single crested hill here in which the sand rock dips towards the southeast throughout. Moreover the very steep dips in the south leg of the basin approaching to the vertical, decrease the surface width of the outcrop to one-half of what it would be if the dip in this portion of the synclinal equalled that in the northern half, 40° to 50°. But still further proof of the accuracy of this structure is afforded in the railroad cuts west of Vineyard station where the basin line of the synclinal shows dips of only 10° rising rapidly each way from this central line until finally, in less than a mile and a half from the quarry, the basin has deepened sufficiently to contain a narrow belt of the Marcellus slates, constantly increasing in width going towards Newton Hamilton.

The Enterprise Sand Co. had originally developed their property by two large open quarries, perhaps a hundred