VIRGINIA.

BEDFORD COUNTY.

LOWRY. M'NICHOLS QUARRY.

The McNichols quarry (105) is located on the Thompson place, 5 miles south of Lowry station, on the east bank of Otter River. There are two dikes exposed on the west slope of a ridge that runs north and south. The dikes' strike is northeast, the dip 75° N. The south dike, where exposed, is about 20 feet wide. In the middle is a band of pure feldspar, varying from 5 to 7 feet wide, with pegmatite on each side. This pegmatite, however, is rich in feldspar, and if care were exercised to eliminate the mica scattered through it much marketable feldspar could be obtained. This dike is opened 25 feet into the hill, being exposed for a depth of 40 feet and across its full width. The north dike, which is separated from the south one by about 30 feet of country rock, shows no band of pure feldspar, but is very rich in feldspar throughout its width of about 10 feet. This pegmatite is very coarsely crystalline and has considerable coarse muscovite scattered through it. Very little material has been removed from this part.

Another exposure of what is probably one of the same dikes is about 150 yards northeast, where pegmatite is exposed for a distance of over 50 feet. This area has not been opened, and the capping material shows muscovite and some biotite. Small lenses of pure muscovite and albite are noted at frequent intervals.

Feldspar from the south dike was analyzed and shows the following chemical composition:

The deformation temperature ranges from 1,260° to 1,265° C. The fused feldspar forms an opaque white mass.

PROPERTIES IN STANDARD PORCELAIN MIXTURE.

This feldspar in the standard mixture vitrifies at 1,265° C., and at 1,350° C. shows slight warping. The porcelain shows a very faint bluish tint. Fired at 1,350° C. this feldspar has a translucency of 0.64 and is cream colored by transmitted light. The total shrinkage is 15 per cent, the drying shrinkage being 3 per cent and the firing shrinkage 12 per cent. Under the raw lead and fritted glazes the color is unaltered.

The American rutile quarry (106) is 8 miles northwest of Arrington, near Roseland post office. The quarry is in a dike about 75 feet wide, which has a northeast strike and is vertical. The dike is divided into two distinct sections by a vertical band of trap rock about 20 feet wide. South of this band the dike consists of a plagioclase carrying a high content of rutile and ilmenite. This part of the deposit is worked and the rutile extracted by means of jigs. No attempt to completely extract the ilmenite is made and a considerable amount of rutile remains in the tailings. Many lenses of albite free from rutile and other minerals are noted in this part of the dike but no attempt to save the albite is made, as the haul is too far to make marketing it profitable.

The part north of the trap rock band is similar to the south part, except that hornblende has replaced the other minerals to a considerable extent. If transportation facilities are provided for the development of this property, the associated minerals can doubtless be eliminated from this feldspar and the latter made marketable. The run of the tailings from the south part of the dike has a deformation range of 1,310° to 1,320° C. and fuses to a yellow brown glass.

PRINCE EDWARD COUNTY.

PROSPECT. PROSPECT QUARRY.

The Prospect quarry (107) is one-half mile south of the village of Prospect. Two dikes have been opened on this property. One has a width of about 20 feet and has been quarried for a distance of 40 feet and to a depth of 15 feet. The other is about 12 feet wide and has been quarried for a distance of 30 feet and to a depth of about 12 feet. A large part of these dikes is a light cream pegmatite containing an excessive amount of quartz and also a large amount of muscovite distributed throughout the mass as small flakes. This part of the dike is, therefore, of doubtful value for pottery feldspar. Lenses of buff microcline pegmatite and lenses of pure buff microcline are present in large amount in both dikes. In the large dike one lens 8 feet wide is exposed. This buff microcline and pegmatite is very low in muscovite content and the pegmatite is low in quartz. No biotite is observed in either of the dikes, and other iron-bearing minerals are absent also. Operations on this property have been intermittent and the quarry was idle at the time of inspection. The dikes have not been exhausted, however.

The buff microcline and pegmatite were sampled to obtain an average of the run of the quarry and this was found to have a deformation range of 1,295° to 1,310° C. It fuses to a pale cream semitransparent glass.

PROPERTIES IN STANDARD PORCELAIN MIXTURE.

In the standard porcelain mixture this material vitrifies at 1,300° C., and at 1,330° C. no warpage is apparent. Fired at 1,330° C. this porcelain has a total shrinkage of 13.4 per cent, a cream color by transmitted light, and a translucency of 0.74. The color is slightly cream when compared with that of the standard trial, and is unaltered under the raw-lead and the fritted glazes.

AMELIA COUNTY.

JETERSVILLE. OLD SCHLEGEL QUARRY.

The old Schlegel quarry (108) is 14 miles northwest of Jetersville. This quarry was opened on a lens of a dike which can be traced for at least one-half mile northeast along the strike. The quarry has a width of about 20 feet and a length of about 40 feet. The workings have caved so that both the walls and the floor are obscured but a narrow face of wall was cleared along the strike and a cream microcline exposed which is free from quartz or other associated impurity. A large quantity of this class of feldspar is reported as being quarried here but a coarse pegmatite constitutes a considerable part of the dike. Numerous small dikes or stringers are noted throughout this country but no attempts have been made to prospect these.

The feldspar samples taken from the old Schlegel quarry were tested and found to have a deformation range of 1,295° to 1,310° C. and fuses to a semitransparent glass free from tint.

PROPERTIES IN STANDARD PORCELAIN MIXTURE.

In the standard porcelain mixture this feldspar vitrifies at 1,300° C., and at 1,330° C. shows no warpage. Fired at 1,330° C. the porcelain has a total shrinkage of 13 per cent, a cream-white color by transmitted light, and a translucency of 0.82. The color of the porcelain is equal to that of the standard trial and is not altered under either the raw-lead or the fritted glaze.

An exposure of pegmatite (109) about 20 feet high occurs at Jetersville pond, 2 miles northeast of Jetersville, where the JetersvillePainesville road crosses Flat Creek.

The Rutherford mica mine (110) is located 2 miles northeast of Amelia courthouse. The dike here is not exposed as the workings, which consisted of a number of shafts, have filled with water and have caved in many places. The width covered by shafts appears to be about 12 feet and the shafts continued along the strike for about 75 feet. There was no attempt at feldspar mining, so far as could be learned, but the dumps about the shafts contain large quantities of a semitransparent albite of exceptionally fine color, and a brilliant green microcline. Small "books" of a clear muscovite are also plentiful. Quartz is present only in the massive form. The

4492°-Bull. 92-16-12