Bulletin . a depth of about 20 feet. In the vicinity of the gem-bearingdeposits are lenses of the soda feldspar clevelandite, with which areassociated lenses of massive albite. This material has a compara-tively high deformation temperature, but has the short deformationcharacteristic of soda feldspar. The quantity of this material, how-ever, is too uncertain to justify extensive investigations. The potashfeldspar, however, which constitutes the major part of this deposit,is of a very uniform quality. It has a deformation temperature of1,270° to 1,285° C. and an excellent color. MASSACHUSETTS.
Bulletin . a depth of about 20 feet. In the vicinity of the gem-bearingdeposits are lenses of the soda feldspar clevelandite, with which areassociated lenses of massive albite. This material has a compara-tively high deformation temperature, but has the short deformationcharacteristic of soda feldspar. The quantity of this material, how-ever, is too uncertain to justify extensive investigations. The potashfeldspar, however, which constitutes the major part of this deposit,is of a very uniform quality. It has a deformation temperature of1,270° to 1,285° C. and an excellent color. MASSACHUSETTS. HAMPTON BLANDFORD QUARRY. The Blandford quarry (121) is one-half mile north of Blandford and4 miles from the railroad at Russell, Mass., in a dike exposed alonga ridge running northwest and southeast. The dike is composed of o For a description of this deposit see Bastin, E. S., Economic geology of the feldspar deposits of theUnited States: Bull. 420, U. S. Geol. Survey, 1910, pp. 26-27,. Scale in miles SKETCH MAP OF PARTS OF CONNECTICUT NEW YORK .SEE ALSO PL. VI,, AND MASSACHUSETTS, SHOWING FELDSPAR DEPOSITS INVESTIGATED FOR DESCRIPTION OF DEPOSITS SEE TABLE 2 CHEMICAL ANALYSES OF SAMPLES. 123 several bands of pegmatite, varying widely in their feldspar of the bands are 12 to 15 feet wide in places and have a con-siderable content of massive feldspar; the deposit also containsmuch massive white sugar quartz. The property has been openedboth on the hilltop and along the face. In one place an openingabout 60 feet long and 20 feet wide has been made, and along thewalls of the dike considerable muscovite of good quality has beenremoved. At the south end of this opening the feldspar is about 10feet wide; whereas at the north end the sugar quartz has almostcompletely replaced the feldspar. Pure feldspar, however, is ob-served in smaller openings to the north of this main opening, and itwould be assumed that the quartz rapidly pinches out beyond thelim
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