Crystalline Limestones of Warren Co., X.J. — Westgate. 377 
plane of the bedding. Yet these outcrops A to E contain 
some of the most coarsely and thoroughly crystalline lime- 
stone of the whole region and limestone carrying as large a 
proportion of accessory metamorphic minerals as any else- 
where. The metamorphism cannot be the result of eruptives 
as there are almost none in the limestone. 
The metamorphism of the Jenny Jump limestones is not 
local, but general; not due to the agency of eruptive rocks, 
but to other causes acting over wider areas and producing 
farther reaching and more uniform effects. In this area the 
crystalline and the blue Cambrian limestones are not inti- 
mately associated. Yet the unchanged blue limestone occurs 
not far from the crystalline at the most northern outcrops of 
the latter. The metamorphism has affected the crystalline 
limestone but not the blue. The reason is clear. The blue 
magnesian limestone had not been deposited at the time of 
the metamorphism of the present crystalline limestone, else 
it too would have been involved in the same changes as have 
affected the crystalline limestones; changes very probably 
produced by the same agents that were at work in the crys- 
tallization of the associated gneisses. The crystalline lime- 
stone is older than the blue Cambrian limestone and is of pre- 
Cambrian or Archaean age. It is difficult to conceive that the 
forces resulting in metamorphism could act over considerable 
areas and then suddenly stop short. If the two apparently 
different limestones are of the same age, the blue limestone 
associated with the crystalline should also have been meta- 
morphosed. A greater agent than local metamorphism by 
eruptives is required, to explain the crystalline character 
of the Jenny Jump limestones. Regional metamorphism, 
which is the only adequate explanation of this character, 
must have occurred at a time previous to the deposition of 
the blue or Cambrian limestone. 
The field relations of tin crystalline limestones and the blue 
magnesian or Cambrian limestone. More or less has been 
written concerning the field relations of these limestones 
while discussing previous points of this paper. In the Jenny 
.lump region they arc nowhere in close and intimate associa- 
tion. The two are said to be in intimate association about 
Franklin, in Sussex county, and that is taken as one of the 
