Pot<t-Arrhit'(iii A(/e of W/i/tr LI iii^-Stoiics. — ^Tdsroi. 107 
will prove these limestoneis to l)ea l(X-ally metamorphosed fossilifer- 
ous limestone. 
In other words, if positive and direct evidence can Ite found 
showing a transition from Ijlue to white limestone, the fact that 
the white limestone lias the aV»ove concomitants does not militate 
again.st the proposition in the least. The problem simply assumes 
another and a totally different phase. Instead of a question of 
geological age it becomes a study in metamorphism. 
In the following paper the writer wishes to present, as con- 
cisely as possible, the evidence which led him to the conclusion 
that the white limestone of Sussex county is but the metamor- 
phosed form of the fossiliferous ])lue limestf)ue. 
The evidence can be summed up under these heads: 
1st. The topographic features of the two rocks. 
This will include, (a) the nature of the dips and the foldings of 
the rocks; (1)) the axes of special disturbance. 
2d. The associated rocks. 
This will include, (a) the accompanying l)edded rocks, (b) the 
eruptive rocks. 
3d. The transition of one limestone into the other. 
This will include, (a) breccias in the white limestone, (b) breccias 
in the blue limestone, (c) graphite and fossils, (d) the actual trac- 
ing (icross the strike and idony the strike from white to blue, this 
occurring in long lines, (e) occurs in many localities, (f) the 
breccias form the Ijoundarv lines. 
1. Topographical features. 
The white and the blue limestones are intimately associated 
with each other. Large areas of white limestone are never widely 
separated from the blue, and not a single outcrop of white lime- 
stone is known by the writer wholly independent of the blue. 
(a.) In former reports and papers on this sul)ject. the dis- 
tinctive feature of the white with res})ect to the blue, has V)een 
•'the universal southeast dip" and the northwest dip of the blue. 
Neither of these statemeiit.s is in accordance with facts. It is us- 
ually difficult to observe the dip of the white limestone on account 
of the extreme metamorphism. Yet the fact that the Avliite lime- 
stones do di}) northwest is plainly to be observed. It freipientlv 
happens that one end of the slope of a hill is white limestone and 
the opposite end of the sIojjc of the hill is blue. Hut whatever 
the direction of tiic dip. they liotli dip in the same direction, 'i'ht' 
