Granite at Mounts Adam and Eve. 639. 



To the latter gentlemen we acknowledge our great indebtedness for 

 assistance. 



Once on the ground, the problems of the blue and white limestone, 

 which have recently been brought to general attention in New Jer- 

 sejj hy F. L. Nason, also attracted us, and the results of the trip 

 became concerned with a wider subject than the petrography of the 

 granite alone. The belt of closely involved blue and white lime- 

 stones, which begins in Warwick Township, of Orange Co., N. Y., 

 and just north of Mt. Eve, runs southwesterly through New Jersey, 

 for a total unbroken stretch of over thirty miles. Isolated patches, 

 usuall}^ of small size, run still further — quite to the Delaware River. 

 The general width varies greatly. At Amity, N. Y., it is two miles 

 across, but elsewhere it rules much narrower, and as stated it may 

 disappear entirely. A detailed sketch of the New Jersey expo- 

 sures is given by F. L. Nason, in the Annual Report of the New 

 Jersey Survey for 1890, pp. 25-50 (The Post-Archaean Age of the 

 White Limestones of Sussex Co., N, J.), and many details and 

 sections are recorded.^ 



A vast amount of attention has been directed to this belt in the 

 past, because it is one of the most prolific sources of tine minerals 

 the world over. The great and unique zinc mines of Franklin Fur- 

 nace and Ogdensburgh-^ are in it, and innumerable localities else- 

 where have contributed their share, not least of which are Amity 

 and Edenville in the tract visited by us. The geological questions 

 are briefly the following. A white crystalline limestone is closely 

 involved with a blue, and rarely fossiliferous one, which latter has 

 been shown to be of Cambrian A^e. The white borders gneissic or 

 granitic rocks, and is abundantly penetrated by masses of granitic 

 affinities, and by others of curious mineralogical composition. In 

 these portions it is copiously charged with interesting minerals. 



1 Additional papers by Mr. Nason have appeared under the same title in 

 the Amer. Gleol., April, 1891, p. 241, and September, 1891, p. 166. The former 

 gives an historical review of opinions advanced in the last seventy years, 

 while the latter is a reply to a review of the New Jersey Report for 1890, by 

 Professor J. D. Dana, in the Amer. Journ. Sci., July, 1891, p. 70. Great 

 credit is due Mr. Nason for his endeavor to base the decision of this question 

 on detailed records of observations, and not on generalities, as was done by 

 most of his predecessors. 



2 In the Transactions of the N. Y. Academy of Sciences for Nov. 1893, 

 J. F. Kemp has given a description of these ore bodies with a bibliography 

 and annotated list of minerals. 



Annals N. Y. Acad. Sci., VII, Feb. 1894.— 12 



