380 J. F. KEMP — GRANITES OF ATLANTIC COAST 



the curious assemblage of eruptives that come to the surface on Cape 

 Ann.* 



Dr. Washington has called the Jatter the " Petrographical Province of 

 Essex County," and in this way has emphasized the peculiar characters 

 of the region. The granites in the central part of the state are more 

 like those elsewhere in New England. 



Rhode Island and Connecticut. — These states have been sufficiently de- 

 scribed in the main part of this paper. 



New York. — Only granites in the southeastern part of New York are 

 here considered. A number of intrusions of a more or less pronounced 

 dioritic character have been noted by F. J. H. Merrill and his assistants 

 in the schistose or gneissic rocks of Westchester and New York counties.f 

 Kemp and Hollick have remarked the dioritic character of the granite at 

 mounts Adam and Eve, in Orange county. Some biotite is present in 

 the rock, but it is a minor component. One can not say, in the present 

 state of our knowledge, to what extent intrusive granites may enter into 

 the crystalline complex of the Highlands of the Hudson, but, so far as 

 information is at hand regarding the undoubted eruptive rocks of this 

 section of New York, it may be stated that the granites depart notably 

 from the prevailing biotite-granites of the coast. 



New Jersey. — True granites as distinguished from gneisses are not prom- 

 inent in this state. Some of a more or less pegmatitic nature have been 

 long known in the belt of white crystalline limestone of Sussex county? 

 and Wolflf and Brooks J have identified the " Losee Pond granite " as an 

 important member in the pre-Cambrian crystallines lying east of Franklin 

 furnace. It is a binary (that is, quartz and feldspar) granite. § 



Pennsylvania. — Pre-Cambrian gneisses are extensively developed in 



*The petrography of the Quincy granite has been set forth in detail by T. G. White in the fol- 

 lowing paper : "A contribution to the petrojcraphy of the Boston Basin." Proc. of the Boston Soc. 

 of Nat. Hist., vol. xxviii, 1897, p. 117. Mr White gives a complete bibliography. Doctor Washing- 

 ton has added an important- note on riebeckite : " Soelvsbergite and Tinguaite from Essex county, 

 Massachusetts." Amer. Jour. Sei., August, 1898, p. 180. Doctor Washington's most important 

 contribution to the petrography of the region will be found in a series of papers entitled the 

 "Petrographical province of Essex county, Massachusetts," which began in the Journal of Geol- 

 ogy, vol. vi. No. 8, November-December, 1898. A full bibliography is given. 



fF. J. H. Merrill : The geology of the crystalline rocks of southeastern New York. Report of 

 the New York State Museum, 1896, p. 30. 



H. Ries : On a grauite-diorite near Harrison, Westchester county. New York. Trans. N. Y. Acad. 

 Sci., vol. xiv, 1895, p. 80. 



J. F. Kemp and Arthur Hollick : The granite at mounts Adam and Eve, Warwick, Orange county. 

 New York, and its contact phenomena. Annals N. Y. Acad. Sci., vol. vii, 1894, p. 638. 



t J. E. Wolff and A. H. Brooks : The age of the Franklin white limestone of Sussex county. New 

 Jersey. XVIII Ann. Rep. Director U. S. Geol. Survey, part ii, p. 431. 



I It is to be regretted that G. R. Keyes and, following him, E. B. Matthews, in the references given 

 below under Maryland, have employed " binary granite " for a granite with both micas. Its use for 

 granites consisting of only quartz and feldspar has been so long established in the older text-books 

 that a change in the meaning only creates confusion. 



