The formal Franklin-Sterling Hill Area

The decision as to what areas to include in this study, and what to exclude, was made cautiously over a period of many years. In any such compilation there must be geographical limits to the area covered. This decision, however, was a difficult one, for surely the minerals of the small, proximal magnetite deposits, the Furnace Magnetite Bed, and the host Franklin Marble, all of the same Precambrian age, and adjacent to or between Franklin and Sterling Hill, are part of the great events which formed these deposits. There are no simple or rational delimiters; any definition is imperfect.

Accordingly, leaning a bit on historical precedent and tradition, and more on geology, the formal definition of the Franklin-Sterling Hill Area was adapted from the "Special Map" (Cook, 1868; Pike, 1899), which was employed in the Franklin Furnace Folio (Spencer et al., 1908), and used by Palache (1935) as well, thus having longstanding utility and special historical significance. This "Special Map" area includes both zinc deposits, the attendant magnetite deposits, and those marble quarries between the zinc ore deposits (Figure 8-4).

In the years since the "Special Map" was drafted, much development has marked the local surface, and extensive geological work has refined our understandings of the subsurface relations. Accordingly, in consultation with Mr. John L. Baum, retired Resident Geologist for the Franklin Mine, local geological and physical landmarks were chosen to define the approximate area of the Special Map and to facilitate its recognition.

The formal Franklin-Sterling Hill Area is defined by the following physical boundaries.

East: The base of the Hamburgh and Sparta Mountains.

West: The eastern edge of the Wildcat Band of marble to the place where it plunges beneath the unconformity. The west boundary north of that point is defined by the Wallkill River.

South: Brooks Flat Road in Ogdensburg, just a bit south of Sterling Hill.

North: A line east-west from the intersection of Route 23 and Route 517 at the Hamburg-Franklin border (formerly known as Hardistonville, and the type locality for the Hardyston Quartzite).

This defined area includes most of the significant local mineral occurrences; the mineral species listed herein all came from within this designated area, and almost all of them occurred within the orebodies or from rocks proximal to the orebodies.

Not far outside this defined area are a few important mineral localities: the Bodnar Quarries in Hamburg and the Lime Crest Quarry northwest of Sparta; minerals known only from those sites are not listed herein, and no descriptions are given.

Copyright © 1995 by Pete J. Dunn			Website by Herb Yeates
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This page created: January 16, 2001