Arclupa)) Plant 123 



IX. — Oil a)i Avchcean Plant from the White Crystalline Lime- 

 intone of Sussex Count jj, JV. J. 



BY N. L. BRITTON. 



Read, January 9, 1888. 



The abuiidance of graphite in certain Archaean limestones, 

 and notably in those referred to the Lanrentiaii system, has of- 

 ten been cited as an indication of the existence of plant-life at 

 th.it remote period, and indeed, has seemed to the writer and 

 others atti'ibntable to no other source, nlthough this view has 

 not fonnd ready acceptance in the minds of many geologists. 

 The mineral generally occurs in these limestones in the form of 

 scattered separated flakes or small masses, often somewhat crys- 

 tiilline in outline, thus affording neither information regarding 

 the luiture of the plant from which it has been derived, nor cer- 

 tainty that it is in i-eality of vegetable origin. Through a for- 

 tunate discovery made last September by Mr. J. I. Northrop 

 and myself, I am able to submit evidence that in one belt of 

 Archaean limestone in the Highlands of New Jersey, the graph- 

 ite has been derived from a plant, and proof that vegetable life 

 existed in that epoch. 



There are two known limestone belts in the New Jersey High- 

 lands. The one is in the eastern part of the area, extending in 

 isolated outcrops from Mendham, Morris County, northeast 

 through Passaic County to Kingwood, and in New York through 

 Orange County to the Hudson. This contains some graphite, 

 but is especially characterized by serpentine and other magne- 

 sian minerals. The other has its southwestern exposures in 

 Warren County, extends through Sussex County, and is also 

 known for a considerable distance in Orange County, New York. 



