and subjected to various physical tests, the results of which for locality are given in detail in Chapter XIX. A tabulation of the physical tests is given in Chapter XVIII.

THE MICACEOUS, TALC-LIKE CLAY.

Immediately below the Alloway clay there occurs, in the vicinity of Woodstown and towards Ewan Mills, a thin bed of white, micaceous, sandy clay, which is quite unique. Where pure, it is snow white in color, though it is not infrequently stained yellow by iron. It has a marked, soapy, talc-like feeling, so much so that in our notes it is referred to as a tale clay, although, strictly speaking, it is not talc at all. The bed is probably never more than 10 feet thick, but it is apparently quite constant in horizon. It is not very plastic and of doubtful value as clay. It is well exposed in the railroad cut just north of Woodstown (170) and at an old pit east of Harrisonville (173).

THE FLUFFY SAND.

Beneath the micaceous, talc-like clay there is a bed of fluffy sand, which, in Burlington county and southwest to Salem county, forms the lowest of the Miocene beds. At its very base there is not uncommonly a layer of pea-gravel a few inches in thickness, but this is not everywhere present. To the southwest, in the vicinity of Quinton and Alloway, its thickness is less than 10 feet, but it thickens to the northeast, having a thickness of 50 feet or more east of Mullica Hill. It extends much farther northeast, but beyond this point its exact limits cannot be determined, since the overlying Alloway clay is absent and the Cohansey sand, which lies above the Alloway clay, is brought into juxtaposition with the "fluffy" sand.

This sand is often, in fact usually, delicately colored in pale shades of pink and yellow, which frequently make a wavy banding, due not so much to stratification as to the irregularities of coloration. This sand contains some lamina and thin beds of clay, but none in the southwestern part of the State that are anywhere worked, and none apparently of commerical importance.

THE ASBURY CLAY.

Stratigraphic relations.-In Burlington and Salem counties the fluffy sand apparently forms the base of the Miocene. In Monmouth county, however, the lowest portion of the Miocene contains numerous beds of clay underlying the fluffy sand and grading upward into it by interstratification. Locally, these clay beds attain considerable thickness, and, where not too deeply buried, form deposits of considerable economic importance. From their development just west of Asbury Park, they may be called the Asbury clay. It is believed that these clay beds lie below the great mass of "fluffy sand," and, therefore, at a lower horizon than the base of the Miocene farther southwest. In other words, it is believed that the successive Miocene formations overlap each other to the northwest, so that in Burlington, Gloucester, Camden and Salem counties its base, where exposed, lies farther up the dip of the formations than in Monmouth county, and consequently the basal beds, as exposed in the former counties, are not so low as those shown in Monmouth county. It is not certainly known whether the Asbury clay forms a single, welldefined bed of wide extent and varying thickness, or whether it is rather a series of overlapping clay lenses, some thin, some thick, separated by beds of fine, loose, light sand, all occupying about the same general horizon. On the whole, the evidence seems most to favor the latter view.

Occurrence. Just west of Asbury Park the clay is well exposed in Drummond's pits (217), where 12 feet of dark clay, with thin laminæ of sand, underlie 8 feet of fluffy sand, with thin clay laminæ. Midway in these overlying beds there is a 6-inch layer of fine quartz gravel. The clay continues some depth below the present workings, a 2-foot bed of sand separating the worked from the unworked clay. The top of the clay is about 26 feet A. T., and its base cannot be less than 10 feet, since the underlying marl is found along the brook just north of the pit. Clay similar in appearance to this, but not so thick, outcrops at intervals for half a mile west along Asbury avenue. Its elevation increases westward. At Decker's pits (216), on the N. J. South

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ern R. R., 5 miles west by north of Drummond's, a thick black clay occurs at an elevation of 110 to 120 feet. Above it and interbedded in its upper portion is a light, fluffy, micaceous sand. At its base the clay is sandy, with some ironstone, beneath which is probably the marl. There is no question but that the clay at Decker's and Drummond's pits belongs to the same general horizon, which has a rise of about 18 feet per mile between the two points.

A mile north of Centreville, clay is known to underlie a considerable area on the property of Mr. D. H. Applegate (270). Numerous borings have shown that it rests upon a bed of marl, at an elevation of 90 feet. Its thickness, including 3 or 4 feet of a surface loam, which may be of somewhat later origin, is 14 to 17 feet. Most of this clay is light colored, but some borings have struck black clay.

On the west side of the Hominy Hills, east of Jerseyville, at Brockelbank's clay pits (214), a laminated sand and clay occurs at an elevation of about 115 feet, and borings have shown a marly sand at 95 feet A. T., the intervening beds being chiefly sand, with clay laminæ; a very sandy phase of the Asbury clay. Very similar deposits occur at the old brickyards, near Shark River station on the N. J. Southern R. R.

These data apparently indicate that the Asbury clay extends as far west as the west side of the Hominy Mills and underlies them, but that in the western portion of the area it becomes very sandy. Borings show that in the vicinity of Pine Brook, at the north, the clay has also thinned out. Sufficient data are not at hand to determine its southern extent. It is not known to occur south of the latitude of Shark river. Within the area thus roughly outlined, the clay is in general deeply buried by the overlying sands and gravels. It is only on the bordering slopes to the lower ground or along streams, which have cut into it. deeply that the clay has been found. Further search for it should be controlled by the fact that the bed dips about 18 feet to the mile to the southeast from elevations of 115 feet on the northwest at Applegate's, Decker's and Brocklebank's to 25 feet at Drummond's, near Asbury Park.

THE EOCENE MARL.

This formation includes the upper portion of the Upper marl bed, which was designated as Blue marl by Prof. Cook. It is found in a limited area in Monmouth county along the valleys of the Shark and Manasquan rivers, where it is seen chiefly on the valley sides. It lies directly beneath the Asbury clay, being often separated from it by an indurated stony layer. It consists of very fine, dark-green sands, which have a slight bluish tinge, and it is quite fossiliferous. These fossils represent a fauna, which is generally regarded as Eocene in age. There is a slight unconformity between these marls and the overlying Miocene beds, indicated by the general overlapping of the Miocene beds upon the subjacent layers, so that towards the southwest the higher beds of Miocene rest directly upon beds lower than the Shark River marl. Since this formation contains no clay beds, it will be dismissed with these few words.