140 



hundred yards, is the calcareous conglomerate, havuig the same 

 composition with that north of Lebanon and New Germantown. 

 Its dip is apparent!}^ to the northwest. 



Pursuing our course to the Delaware, we next meet the con- 

 glomerate in a belt of more than a mile wide, between Milford 

 and Spring Mills, coming to the river nearly opposite Gallows 

 run. It rests conformably upon the upper layers of the red sand- 

 stone, which it joins probably about one mile to the northwest of 

 Milford. Dipping to the northwest, or directly towards the 

 eastern base of the Musconetcong Mountain, its near proximity 

 renders the conclusion certain, that it meets the strata of the hill 

 in an unconformable position. 



Upon the Delaware, the rock which immediately overlies the 

 argillaceous red sandstone, and soft argillaceous shale, is a siliceous 

 conglomerate of great thickness, which is finely developed along 

 the banks of the river for the distance of a mile, crossing the 

 strike of the beds at an acute angle. The principal part of the 

 pebbles in this portion of the formation are from the primary 

 rocks, being chiefly quartz. They present a great diversity of 

 size, varying from the dimensions of a pea to huge rounded 

 masses, weighing from sixty to one hundred pounds. 



Higher up the river we meet with another conglomerate, the 

 representative of the true calcareous variety, differing obviously 

 in composition from that just described, from which it is probably 

 separated by intervening beds of red shale. This upper con- 

 glomerate is a less finely cemented rock, and includes a con- 

 siderable proportion of calcareous matter, both in the limestone 

 pebbles and in the imbedding paste. The fragments are less 

 rounded and water-worn than in the conglomerate below. Some- 

 what angular fragments of a bluish compact limestone are 

 frequent in the rock, while the siliceous mass exhibits but little 

 corrosion from atmospheric agency ; this more calcareous stratum 

 presents on its surface a loose cellular structure, showing innu- 

 merable pits and cavities, from whence the limestone pebbles 

 have been dissolved. A little below Johnson's Ferry, the rock 

 near the road is thus greatly weather-eaten. 



This upper calcareous conglomerate rarely occurs, except in 

 the neighbourhood of the regularly stratified limestone of Forma- 

 tion II., along the base of the primary hills. It is in this position 



