THE CONGLOMERATES AND THEIR DISTRIRUTION 145 



sea was admitted on a thick mantle of disintegrated rock material which 

 its strong tides took up and transported.* 



DISTRIBUTION OF THE CONGLOMERATES 



The distribution of the conglomerates is one possessing very consider- 

 able interest. In the Connecticut Valley area these rocks generally form 

 an eastern and northern and sometimes a western border to the area. 

 In the New York-New Jersey area they form likewise a border, but 

 on the northwest. In the southern areas also, as well as within the 

 small Pomperaug Valley area of Connecticut, they are generally mar- 

 ginal to the areas as respects their distribution. So general is this ob- 

 servation that the few cases where the exposures of conglomerate are 

 found distant from the boundaries of the areas, may generally be best 

 explained through displacement by the block-faulting which has every- 

 where prevailed. Within the Mount Toby conglomerate area of the Con- 

 necticut valley, which is somewhat removed from the margins of the 

 Newark of that region, Emerson f found islands of crystalline rocks 

 from which the material could have been derived. The material of the 

 Newark conglomerates is almost entirely derived from the metamorphic 

 rocks by which they were surrounded. The general lack of correspond- 

 ence between the material of the conglomerates and that of the contigu- 

 ous portion of the wall of crystallines has led Emerson to appeal in part 

 to shore ice and in part to transportation by strong tidal currents, which, 

 in the Connecticut Valley area, he supposes to have moved northward 

 along the western wall and returned along the eastern border of the 

 area. An even more marked lack of correspondence along the north- 

 western border of the New York-New Jersey area, Kiimmel would ex- 

 plain by vertical displacement along fault-walls, a theory which might, 

 it would seem, be applied with equal force to the Connecticut Valley 

 area. In the southern areas the conglomerates seem to be most abun- 

 dant along the western margins of the areas, and it may be said that the 

 distribution of the conglomerates, as regards the areas as a whole, seems 

 to be best accounted for, and, in fact, the formation has been generally 

 described, as a basal conglomerate of the system. Outside of New Eng- 

 land its general restriction to the western borders (without regard to the 

 displacement by faulting) is most in accord with this view, if the western 

 border of the province in which Newark areas occur be regarded as near 

 the western margin of a large area of Newark deposition, owing to the 

 initial dip of the formation. This explanation is also in harmony with 



*0p. eit,, p. 373. 

 fOp. cit., pp. 361-363. 



