up to a plastic mass in the laboratory had an air shrinkage of 6.6 per cent. Its tensile strength was 110 to 130 pounds per square inch.

Condition,

steel-hard slightly absorbent slightly absorbent

The clay was thoroughly viscous at cone 27, hence it is not a fire clay.

Blue Anchor.-Considerable clay, partly for terra cotta, has been dug around Blue Anchor, and shipped from there. One of these pits (Loc. 202), not being worked in 1902, showed at least 9 feet of light, bluish-gray clay, with yellow sandy clay in places. Above this is 2 to 3 feet of pebbly sand. A small sample (Lab. No. 692) that was taken for a partial test, worked up with 38.2 per cent. water and had 7.3 per cent. air shrinkage. Its average tensile strength was fair, being 146 pounds per square inch. It burned as follows:

This could be classed either as a terra-cotta clay or buff-brick clay. It is not a fire clay.

Another pit (Loc. 204) is intermittently operated by Wm. Brimfield, along the railroad.

Prof. Cook noted1 the occurrence of clay near Conrad, one mile south of Tansborough. The clay was dug at one time to make pipe, terra cotta and fire brick, and the section given was:

Stripping,

Clay, ....

White and yellow quartz sand.

6 in. to 3 ft.

5 to 16 ft.

1

1 1878 Report on Clays, p. 258.

General view of Hatch & Son's clay pit, at Fish House.

General view of the Eastern Hydraulic Press Brick Company's works at Winslow Junction. The long sheds on the left are for storing clay, and to the left of those the clay is seen spread out for weathering.

A cemented sand layer was found under the clay in places. It is said that the clay could be traced for a mile southeast of the pits. It was sandy, and its color bluish white, buff, and chocolate.

The composition would indicate a clay of buff-burning qualities, but not a refractory one, for the per cent. of fluxes and sand is too high. (See Silica, p. 312, and Fire clays, p. 311). Its composition resembles that of some stoneware clays.

The crude clay could all be used for pipe according to Prof. Cook, but for finer and ornamental terra cotta it was washed.

Pleistocene.

Fish House. The deposits at Fish House (Loc. 137) have already been described in considerable detail in Chapter VI.

Two large excavations have been made, from one of which with a working face varying from 15 to 27 feet in height, clay is now dug at several points (Pl. XLII, Fig. 1).

Most of the clay is dark, almost black in color, with occasional layers of coarse black sand and much organic matter. Lumps of lignite are not uncommon, but pyrite was not noticeable. The upper limit of the black clay varies, and at the end of the excavation nearest the factory there is a 2-foot layer, low in organic matter and sand, which is sufficiently plastic for pottery purposes and has been used for stoneware.

It is found in actual practice that it is undesirable to use the black clay alone, and that a certain amount of loam must be added to it. This decreases the fire shrinkage and makes the clay easier to burn, for the black clay alone has considerable organic matter. The physical properties of the black and of the brick mixture can best be compared by placing them in parallel columns.

The black clay, in spite of its high tensile strength, does not feel

very plastic when wet, and the brick mixture is much more sticky.

The following analysis was made of a green brick, as representative of the run of the bank: