at Riveredge, a little south of the depot, in a temporary excavation. Here the section was as follows:

"(3) Sand, 4 feet.

“(2) Clay and sand, interlaminated, 6 feet.

"(1) Clay, black from the presence of organic matter. "The old soil in this case was about 10 feet above sea level. "These sections show that after the clay was deposited, the surface was exposed for a time, and that vegetation grew upon it, after which it was depressed sufficiently to allow of the deposition of the overlying sand.'

་་་

Clay of the lower Passaic valley.-Clay, very similar in appearance to that at Hackensack, was formerly dug in the valley of a little creek on the west side of the Passaic, one-half mile or more below Passaic Bridge. It lies beneath several feet of coarse gravel, which increases in thickness towards the hill. The clay is reported to be 13 feet in thickness, the upper 6 or 8 feet being yellow, the lower part blue. Owing to the heavy overburden it is not readily available.

Clays of the upper Passaic basin.-Clay occurs over wide areas in the basin of the upper Passaic and its tributaries in the area formerly occupied by the glacial Lake Passaic. It underlies all the area of Great swamp and the surrounding low ground, where it does not occur above an altitude of 240 feet. The clay of the eastern half of this area, as far west as the road from New Vernon to Gillette, is covered with fine sandy loam, which east of the longitude of Green Village changes into sand and gravel. Clay more or less buried by sand and gravel has also been found 1) south of Morristown, 2) on the banks of the brook southwest of Convent and 3) at the bottom of deep wells southwest of Madison.

The clay in the Great swamp area attains a considerable thickness. Wells 25 or 30 feet deep do not pass through it except along the edge near the higher ground. At one locality, a mile and a half south of Green Village, clay is reported to be over

1N. J. Geol. Surv., Vol. V, Report on Glacial Geology, pp. 616-619.

2N. J. Geol. Surv., Ann Rep. for 1893, and Vol. V, Report on Glacial Geology. See, also, Plate X, in pocket, for the outline of Lake Passaic.

Little Falls.

Fig. 2.

Another view of same, showing many stones in the clay and at the top of the bank the marks that have been made by the wedge in breaking off masses of it. Laminated lacustrine clay occurs at the bottom of the bank under the stony clay.

a hundred feet thick. Outside the swamp, similar clay occurs at somewhat greater elevations, but yet within the limits occupied by Lake Passaic. At the clay pits south of Morristown (elevation 310-320 ft.) it is overlaid by 2 or 3 feet of glacial till. Three miles south of Morristown, on the property of Mr. F. F. Lippman, slightly stony clay is exposed along the road, its vertical range being 30 feet. Between Second mountain and Long hill, along the Passaic and Dead rivers, there is considerable clay at elevations below 225 feet. This clay may in part be postGlacial, since it is hardly above the present flood plain of the river.

Northeast of the morainal ridge which extends from Morristown to Chatham, lacustrine clay occurs at several localities, chiefly at low levels. Some of it may be in part post-Glacial in origin, but other beds are wholly of earlier date. The clays found in the marshes along the Whippany river belong to the former class, while a brownish-blue clay, on the hill midway between Whippany and Hanover, at an elevation of 230 feet and overlain by several feet of glacial till, belongs to the second class.

North of West Livingston a low area (200 ft.) seems to be underlain with clay. A mile and a half northwest of the south end of Hook mountain the Rockaway river has cut through a thin coating of glacial sand and gravel into underlying clay. Extensive deposits are said to occur on the property of J. B. Ricketts, near Parsippany. In the vicinity of Little Falls, Singac and Mountain View there are extensive areas at low levelsunderlain by clay which is dug at a number of points, Plate XVI. In places the laminated clay is overlain by till, some of which is not too stony to be used also for brick; elsewhere by stratified sand and gravel. Clay also underlies the low ground northward from Mountain View nearly to Preakness, but it is deeply buried by sand and silt, except along the borders.

The clay at the lower levels is always finely laminated, the thin clay laminæ being separated by fine sandy partings. It is calcareous and frequently contains concretions of carbonate of lime, some of which are shown on Plate IV (p. 24). These are very abundant in certain layers, occurring in clumps at certain

horizons rather than equally distributed. They vary greatly in size and shape, some cylindrical forms being 6 inches in length. The clays at higher levels are usually less distinctly laminated and generally contain a few glacial pebbles. Locally, as at Morristown, they grade upward into stony till.

Other localities.-Clay apparently of Glacial age has also been observed at a few other localities. It was formerly dug for brick along Clove brook near Sussex (Deckertown), not far from Fuller's mill.

At Somerville a red clay occurs at Ross' brickyard, where it is used for common brick. It contains many bits of waterworn red shale and some yellow quartz pebbles, which are more common in the upper layer. The body of the clay is composed of the finest material derived from the disintegration of the red shale. It is clearly a slack water deposit, and the readiest, but not necessarily the only, explanation, is that it was formed during the Glacial period, when the Raritan valley was temporarily dammed by sand and gravel discharged into it from the north near Bound Brook.1

CAPE MAY CLAYS.2

Origin.-Around much of the coast there is an ill-defined terrace 30 to 50 feet above tide. In some places it seems to have been cut by the waves in older formations. In other localities it has been built by them of debris gathered where their work was destructive. Terraces, corresponding in elevation to these wavecut and wave-built forms, extend up the streams, and, except near the sea, are the result of stream action. Traced up the Delaware bay, these river terraces, although often poorly defined, pass into that formed of the glacial gravels brought down the Delaware river from the melting glacier farther north. Corresponding stream terraces occur along the tributaries of the Delaware river below Trenton, just as they do along the valleys leading to the Atlantic coast. The fact seems well established that

1

1 Ann. Rep. State Geologist of N. J., 1892, p. 123.

2 See N. J. Geol. Surv., Vol. V, Report on Glacial Geology, for a fuller discussion of the Cape May formation.