BERLIN TO ATLANTIC CITY. Distribution. Fig. 30 shows the relations from Berlin southeast to Atlantic City. The section is extended northwest of Berlin, and takes in Houghton's Hill, which is somewhat out of line. The line of the section is along the divide between Mullica River and Great Egg Harbor River, where remnants of Bridgeton are considerable. The formation has been removed from the basins of these streams, except on the crests of isolated hills; but the remnants are so disposed as to leave no doubt. that they are parts of a once continuous formation (p. 64). About Hammonton, the base of the formation has an elevation of about 110 feet, but as everywhere else, it declines to the southeast. At Elwood its base is down nearly to 80 feet, and at Egg Harbor City nearly 20 feet lower. Between Hammonton and Egg Harbor City, it is found on divides only, and covers a relatively small part of the total area. It is well developed about Hammonton, especially to the south, in a small area at Banard Station, and on the more conspicuous elevations east of Da Costa, and over much of the area between Elwood and the western border of Egg Harbor City. Small areas occur 3 or 4 miles northeast of Elwood. Another small area to be mentioned is that southwest of Folsom, at an elevation of about 90 feet. In much of this area the formation is thin, and represents the base of the formation only. The Constitution. Lithologically the formation is a unit from Berlin to Pleasantville, though not without variations. coarse arkose sand, the bits of Triassic shale and crystalline rock, and the structure remain much the same throughout; but the distinctive red shale and the bits of crystalline rock become less abundant to the southeast. They become so scarce, indeed, that they do not appear in every exposure, especially if the base of the formation is not seen. It is to be remembered that bits of shale and crystalline rock are rare at some points well to the west, as at Williamstown Junction and Blue Anchor. In general, too, the Bridgeton material becomes finer to the southeast. Ex at the tures at F locali cially Ex grave sand In so expos more At coars seen the and of th certa are v In areas ton. mile R. F tion 5 to is t mat the saul and her san lar side Exposures. Good sections have been seen in the railway cut at the sanitarium near Hammonton, where the distinctive features of the formation are well shown, and in the railway cut at Folsom, 3 miles southwest of Hammonton. At the last locality, the foreign constituents (shale, schist, etc.) are especially abundant, and in large pieces (Fig. 9). Exposures are common east and south of Hammonton in gravel pits and road cuts. Many of the cuts are in the Cohansey sand beneath the Bridgeton, rather than in the Bridgeton itself. In some of the pits, only the upper part of the Bridgeton is exposed, because this part is more gravelly than that below, and more compact by reason of its content of loam. At Elwood the exposures show the same features with a coarse layer at the bottom at many places. A good exposure was seen 11⁄2 miles northeast of Elwood, on the road to Batsto, in the 121-foot hill. Here 52 feet of compact gravel of quartz and chert overlay 21⁄2 feet of loamy gravel. About Egg Harbor City and farther east, the separation. of the Bridgeton formation from the Pensauken becomes uncertain, for the gravel and sand concerned sink to low levels and are well exposed in but few places. In the vicinity of Pomona and Pleasantville, there are large areas of gravel with greater thickness, which are perhaps Bridgeton. There are good exposures in road-gravel pits 1 and 2 miles southeast of Pomona Junction, and also on the P. and R. R. R., a mile north of Pleasantville, and near Farmington Station. The exposures between Pomona and Pleasantville show 5 to 10 feet of Bridgeton material. In its general character it is typical of the formation, except that shale and crystalline material are wanting. The abundance of soft cherts is one of the features which suggest its Bridgeton, rather than Pensauken age. This chert must have been hard when deposited, and the decay is subsequent. The upper part of the formation. here has more gravel and loam than the lower part, and less sand. The stratification is much more distinct and more regular in the lower part than in the upper. This point, alone considered, suggests a marine, rather than a fluviatile origin. Base.-Northwest of Berlin, the Bridgeton base has an elevation of about 200 feet. Thence it declines southeastward to 160 feet at Wilton, 140 feet at Blue Anchor, 110-120 feet at Hammonton, about 100 feet at Da Costa, 80 feet about Elwood, and 60-70 feet at Egg Harbor City and Pleasantville. The correlation of the Bridgeton at the southeast is somewhat uncertain, and its separation from the Pensauken may be questioned; but the decline from Berlin to Elwood, if continued, would bring the base of the formation down to the level indicated, at Pleasantville. The constitution of the sands and gravels at the higher levels near Pleasantville is consistent with this interpretation. If the gravels and sands of the higher levels about Pleasantville are Bridgeton, the base of the formation declines about 150 feet in 36 miles, giving it a dip of a little more than 4 feet per mile. The base of the formation shows some irregularities, but they are of a small sort, and in keeping with those farther northwest. THE WOODMANSIE PHASE. Several cross sections from northwest to southeast, across the Coastal Plain, illustrate the general relations of this phase of the formation. ARNEYS MOUNT TO TUCKERTON. Distribution.—The area through which this section (Fig. 32) runs is mostly in the basins of Mullica River and Rancocas Creek, the two largest streams of the Coastal Plain in New Jersey. The area from Arneys Mount to Apple Pie Hill (near Harris Station) is in the drainage basin of Rancocas Creek, while the area southeast of Apple Pie Hill is in the basin of Wading River, a tributary of the Mullica River. The section is extended to the vicinity of Kinkora on the Delaware. The conspicuous features of the section are (1) the broad lowland to the northwest, near the Delaware, (2) Arneys Mount and Apple Pie Hill, and (3) the upland at Munion Field near the ocean. Arneys Mount is capped with Cohansey sand. Apple Pie Hill has a few feet of gravel, which is regarded as a remnant of the Beacon Hill formation. The gravel is of quartz and chert, in proportions of about 4 to 1, with a little sandstone and quartzite. If the Beacon Hill formation once covered Arneys Mount, as it probably did, it was at a level higher than the top of the present hill. Scattered pebbles of Beacon Hill type on the crest of the hill suggest such a former covering. A plain from Apple Pie Hill (208 feet) to Bear Swamp Hill (165 feet), and to another 147-foot hill to the southeast, would, if carried northwest, have an elevation of about 250 feet at Arneys Mount (20 feet above its top). This probably represents about the appropriate level of the former Beacon Hill cap here. Carried southeastward, such a plain would have an elevation of 140 to 160 feet at Munion Field, and this is probably the approximate Beacon Hill level of that region. Fearings Hill (about 2 miles northwest of Fountain Green) has about the same altitude as Houghtons Hill. Its gravel cap has the same topographic relations as the gravel on Houghtons Hill (Fig. 24), Point Pleasant (Camden County) (Fig. 22), and Jacobstown (Fig. 33), and is referred to the Bridgeton formation. The gravel itself is not of such a character as to give especial force to this correlation. Northwest of Apple Pie Hill (South Park) there are gravel beds 4 to 10 feet thick, at an altitude of about 140 feet, which probably are Bridgeton (possibly Pensauken). The same may be said of the gravel about Munion Field at elevations of about 120 feet. Some of the features of these gravels which seem difficult of explanation are probably connected with the shifting of the main divide of the region from near Arneys Mount, to its present position, near Apple Pie Hill. Constitution. The gravels at South Park, at an altitude of about 140 feet, and in the vicinity of Bear Swamp Hill, at 120 to 160 feet, consist mainly of quartz and chert, but they contain bits of ironstone, which seems to rule them out of the Beacon Hill formation. The absence of the ironstone, so far as ex posures show, and the abundance of the soft chert at Apple Pie Hill, together with its topographic position, seem to place the gravel of that place with the Beacon Hill formation, though the correlation is less decisive than could be desired. In the Beacon Hill formation the cherts are weathered characteristically. The chert pebbles seem to be made up of an irregular network of harder and more insoluble material, filled in with. less durable material. On weathering, the less resistant parts become whitish powder, while the skeleton remains hard. At the surface, the decayed part is carried away and the skeleton remains. In secondary gravels derived from the Beacon Hill, the old networks are more or less broken and worn. Occasional fossils in the chert point to its origin from Devonian formations. The quartz in the gravel is vein quartz largely. On weathering, the pebbles develop a columnar structure. This may go so far that the little columns separate from one another. Some of the pebbles may be crushed in the hand, even when their outer forms are still perfect. In gravels derived from the Beacon Hill gravel, there are splinters from these pebbles of columnar structure, but decayed pieces of quartz are much less common than in the original Beacon Hill formation. In the vicinity of Tuckerton, the section shows gravel and sand interpreted, though not without reservation, as Pensauken. No facts concerning these sands and gravels are known which would preclude their deposition by streams or by the ocean. Since they were deposited, the ocean has doubtless encroached on the shore, carrying away the shoreward part of the formation as originally laid down within the limits of the State. Correlation. From the foregoing it is apparent that the basis for correlating any gravel and sand along the line of this section with the Bridgeton formation, is rather insecure. Such correlation must be based on topography more than on anything else. It is to be noted that the possible Bridgeton beds at 160 feet at Bear Swamp Hill, and at 126 feet at Munion Field, are considerably nearer the ocean than the areas of Bridgeton at corresponding levels in other sections. So far forth, this would suggest the greater (pre-Bridgeton) age of these gravels. ΤΗ the o sea h at M earlie paris Willi ins d The Pie Brid Elme near to th appr level Mur been niuch at th degr T but at th Ran west brin man wha Pen sect Τ the mai |