Clay bank at Budd's brickyard, Camden, showing the massive character of the Clay Marl I, and the drainage hole in the foreground into the Raritan sand. The vertical and horizontal marks on the clay are the impressions made by the spades in digging.

there are frequent exposures along roads and gullies. Farther southwest its outcrop is shown on Plate X where it has been combined with Clay Marl I. Over the greater portion of this belt, however, there is a mantle of Pensauken gravel or of displaced material of greater or less thickness, so that the presence of the clay is not always manifest on the surface. Except, however, where this mantle is of considerable thickness, the clay is commonly exposed along stream banks, gullies and road cuts.

Clay Marl II is utilized wholly or in part for brick and draintile at the following places: National Fireproofing Company, Lorillard works, Keyport (224); Edward Farry, Matawan (228); Dunlap & Lisk, Matawan (231) (for flower pots); Jamesburg Reform School (295); Reed Bros., Hightstown (194); John Braslin & Sons, Crosswicks (110); James C. Dobbs, Collingswood (144); Augustus Reeve, Maple Shade (149), and Theo. Saucelein & Son, Maple Shade (150). At many other localities the clay is equally as good as at these points. Numerous samples have been taken both from localities now worked and also from undeveloped parts of the bed. The tabulated results of these tests are given in Chapter XVIII; and in Chapter XIX the various localities in each county are described.

CLAY MARL I (MERCHANTVILLE CLAY).

Character. The lowest member of the Clay Marl series is also a clay, but so different in its composition, in its mode of weathering and its lack of numerous joints that it has been found easy to differentiate it from Clay Marl II, and entirely practicable to map it as a separate bed. Clay Marl I is a black, glauconitic, micaceous clay, more sandy than Clay Marl II, and generally less brittle and more greasy. The upper and basal portions of this bed are commonly much more glauconitic than the middle part, and have been dug for marl at a number of points, but their use for this purpose has not been extensive. The lower half of the bed, both the marly and nonmarly portions, are usually massive and nonlaminated (Pl. XVIII, Fig. 2). The upper portion, however, particularly the nonmarly part, is more sandy and

often distinctly laminated. Fossils are quite abundant, particularly in the glauconitic portions, and are more frequently found than in Clay Marl II.

The weathered portions of this bed are very characteristic. When marly they form an indurated, cinnamon-brown earth, in which the small black grains of marl are distinctly seen. When more sandy, the weathered portion has a peculiar "pepper and salt" aspect. The weathered part of the nonmarly portion is less characteristic, being sometimes a chocolate color and resembling the weathered portion of Clay Marl II. Where sections do not occur, the bed may be traced most readily by the rusty cinnamon brown color of the weathered basal and upper portions.

The

Stratigraphic relations.—The transition from Clay Marl I to Clay Marl II is generally accomplished within 1 to 3 feet. When exposed in section there is rarely any question as to where the division between the two formations should be made. base of this bed is the base of the Clay Marl series. Wherever it has been seen it rests upon a loose, coarse, lignite-bearing sand or a sand with thin seams of black clay. Not infrequently the upper few inches or a foot of this sand is cemented into an ironstone. At some pits where this clay is dug it is only necessary to break through this crust to the loose sand beneath to secure perfect drainage (Pl. XVIII, Fig. 2).

The contact of the black marly clay or its rusty-brown weathered phase and the Raritan sand beneath is shown, 1) in the high bluff on the shore of Raritan bay northeast of Cliffwood; 2) at the clay pits on the west side of Matawan creek; 3) in several ravines between Morristown and Cheesequake (Jacksonville); 4) in the vicinity of Jamesburg; 5) at several points near Bordentown and Kinkora; 6) on Pensauken creek north of Maple Shade station; 7) at Budd Brothers' brickyard, Camden; 8) and at numerous other points southwest of Penns Grove. In Monmouth county heavy beds of black clay occur in the Raritan, not many feet below the contact with the Clay Marl. These beds have sometimes been included in the Clay Marl series, but that they do not belong there is at once apparent to anyone who makes a careful study of the two series. This is particularly the case if the contact between them is traced from the southwest,

where the contrast is, if anything, more definite than in Monmouth county.

The thickness of Clay Marl I increases slightly from northeast to southwest. In Monmouth county its thickness is about 35 feet, at Bordentown it is 60 feet, and in Salem county about the same. Its outcrop across the State is shown on Plate X, and more in detail for the Matawan region on Plate XII.

Localities. At the present time Clay Marl I is used wholly or in part at the following places: Edward Farry, Matawan (228); Pennsylvania Clay Company, Matawan (226); Dunlap & Lisk, Matawan (230); Reed Brothers, Hightstown (193); The Bordentown Brick Company, Bordentown (109); Murrill Dobbins, Kinkora (113); Augustus Reeve, Maple Shade (149), and Budd Brothers, Camden (143). The results of tests upon samples of this bed and those from other localities are given in Chapters XVIII and XIX.

THE RARITAN CLAY SERIES.

Character. The Raritan or Plastic Clay series, as it was called by Dr. Cook, is the lowest and oldest of the three divisions of the Cretaceous in New Jersey. It consists of a number of beds of clay, sand, and locally, of gravel. The clays are of various kinds, from nearly white or steel-blue fire clay of the highest grade to black, sandy clay, containing varying amounts of pyrite and sulphur, and used only for common brick. Some of the sands are nearly pure quartz, sharp and angular in grain, suitable for a high grade of fire sand; others are highly micaceous, or lignitic, or arkose. Some of the latter, composed of coarse grains, or even pebbles of quartz and decomposed feldspar crystals, form the beds of so-called "feldspar" used in the manufacture of fire brick. Along the Delaware river, beds of gravel and cobble stones are known to occur locally, but in Middlesex county nothing larger than very coarse (pea) sand has been seen.

The Raritan series is characterized by the rapid alternation of strata, the abrupt transition both vertically and horizontally from one to another of these beds, and by the absence of any

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