I12 NEW YORK STATE MUSEUM 
minilig was at one time in progress, the developments consisting of 
five shafts, some from 250 to 300 feet deep, a series of cross adits 
driven at intervals from the base of the ridge in which the shafts 
were sunk, and about 1200 feet of drifts, which opened up a band of 
magnetite about 12 feet in width, dipping very steeply to the north- 
west. Not more than 6 or 7 feet of the ore was of shipping quality, 
the rest being leaner admixtures of ore and rock, which, however, 
is capable of concentration. At No. 5 shaft there are at the present 
time about 500 tons (estimated) of sorted ore on the dump. At the 
southwest end the ore body is cut by a pegmatite dike of consider- 
able thickness, since it was necessary to drift for 50 feet through 
the dike in order to reach the ore again on the opposite side of it’; 
but little ore was taken from this part of the mine, as it was soon 
thereafter closed down. The composition of the ore as given by 
Putnam (op. cit.) is, iron, 57.23 per cent and phosphorus, 0.359 
er Ceiae, 
The ore and associated rock contain many features of petrographic 
interest, but a detailed discussion of these features is not here advis- 
able. In brief, the syenitic facies of the Pochuck seems to have 
invaded and thoroughly soaked the Pochuck-Grenville, and to have 
been in sufficient quantity to furnish a mass of its own. During 
the closing stages of consolidation and during, and slightly over- 
lapping the replacement period, slight movement resulted in 
primary granulation, strain, and in the production of a 
eneissoid structure in the Pochuck syenite, which in places is 
almost dioritic in its feldspar content. The ore itself, more or less 
affected by this movement, has replaced by pneumotectic*° or 
deuteric *° (magmatic end-stage) processes the associated rock; and 
slight fractures in the ore are healed with the ultimate product, 
quartz, which with feldspar, has, as pegmatite, cut the ore in places. 
The Sackett workings. These are immediately southwest of 
the Sunk mine, but the ore body is offset 50 or 75 feet by a transverse 
fault. The Pratt mine is essentially an extension of the Sackett. 
Each consists of open cuts extending along the strike of the ore for 
a distance of about 200 feet in the Sackett workings, north of the 
highway, and 300 feet in the Pratt workings, south of the highway. 
Both mines in addition were worked through vertical shafts, which 
154 Putnam, B. T. Tenth Census Report, 1880. 
155 Graton, L. C., & McLaughlin, D. H. Further Remarks on the Ores of 
Engels, California; Econ. Geol. 13: 81-89. 1918. 
156 Sederholm, J. J. Synantetic Minerals and Related Phenomena; Bull. 
de la Com, Geologique de Finlande No, 48, p. 141-42, 
