Bridgeton Formation — Locae Detaies. 59 



range, for the purpose of bringing out the relations of the Pen- 

 sauken formation. 



In this section the Beacon Hill gravel appears at one point 

 only, namely, in the Clarksburg hills, where its base has an 

 elevation of about 360 feet. This alone would give little clew- 

 to the surface in the Beacon Hill time, but from the sections of 

 Figs. 34 and 35 (p. 136) more is known of it. 



On the Rocky Hill range there is a meager scattering of 

 gravel at levels between 300 and 400 feet. These traces of gravel 

 are in accord with the hypothesis that the Beacon Hill forma- 

 tion once covered the ridge. 



Bridgeton base southeast of Clarksburg. — The data for the 

 reconstruction of the Bridgeton base along the line of this sec- 

 tion leave much to be desired. Southeast of Clarksburg there is 

 a series of elevations ranging from 250 feet near Carrs Tavern 

 to 96 feet at Island Heights. The gravels on the hills, which 

 range from an altitude of 190 feet near Francis Mills to 160 

 feet at Cassville and to 150 feet in the vicinity of Lakewood. 

 are regarded as most probably of Bridgeton age. 



The volume of material near Lakewood is much greater than 

 at the 190-foot level at Francis Mills. Its elevation at Lake- 

 wood is 150 feet, more or less. In constitution it is very unlike 

 the gravel near Clarksburg, but very similar to that at Barnegat, 

 which is like that of Hammonton and Vineland, except for the 

 absence of shale and crystalline material. The Lakewood and 

 Barnegat gravels are alike in coarseness, proportions of sand 

 and gravel, structure (for example, the long, horizontal lines 

 of pebbles seen in section), compactness, color, cementation, etc. 



From Lakewood to Island Heights, the surface declines from 

 150 feet to about 50 feet at Toms River. Most of the surface is 

 covered with gravel. It is doubtful if all of it is of the same age, 

 but the differentiation of its parts, if its parts are different, is 

 difficult. The gravel at the lower levels carries more ironstone, 

 etc., and less soft chert, relatively, than that at the higher levels. 

 It is possible here, in various cuts, to recognize about the same 

 distinctions, with reference to constitution, that obtain in the 

 Bridgeton, Pensauken, and Cape May elsewhere. It seems prob- 



