22 Quaternary Formations of Southern New Jersey. 



lower Delaware, it would help to explain the southeastward ex- 

 tension of the arkose phase of the formation, and the occurrence 

 of arkose material and its accompaniments, at the localities just 

 mentioned. 



The former drainage. — The considerations seeming- to point 

 to the course of the ancestor of the Hudson River across New 

 Jersey along - the Amboy-Bordentown valley, are as follows : 

 (i) The great volume of the Bridgeton sediments, calling for a 

 large amount of running water, if the deposits are fluviatile; 

 (2) the character of the sediments, pointing distinctly to a 

 northerly source, a character which is quite as evident at the 

 northeast (as about Amboy) as at any point in the valley farther 

 southwest; (3) the tendency of rivers to choose courses along 

 the contact of the Coastal Plain formations with the older and 

 harder formations makes this the appropriate site of a great 

 valley; (4) the topography and drainage south of the Amboy- 

 Bordentown valley, in the eastern part of the State, suggest that 

 drainage flowed northwestward until recent times. Between 

 Matawan and Freehold, for example, Deep Run and Matchaponix 

 Brook, leading to the northwest, are the dominant streams, and 

 their courses suggest a former connection with a southwesterly 

 flowing stream. Matawan and Cheesequake creeks, flowing east- 

 ward, are of minor importance, and apparently younger. 



The gap in the Rocky Hill range at Kingston probably was 

 utilized by the Raritan when it flowed up the present Millstone 

 valley to join the main stream flowing southwest toward Borden- 

 town. The gorge was probably started after the Beacon Hill 

 epoch. The configuration of the gap itself suggests two stages 

 of history. Its upper part (above the level of 160 feet) is 

 broader, and that below is narrower. The upper part is probably 

 pre-Bridgeton, the lower post-Bridgeton. The part above the 

 1 60- foot level perhaps goes with the general plain of erosion 

 which now has an altitude of about 200 feet in the region from 

 Freehold to Berlin, and at Pennington, and is somewhat lower 

 farther south. The river which flowed through the upper part 

 of the valley of Stony Brook, probably joined the same stream 

 that the Raritan joined. 



