MAGNETITE IRON DEPOSITS OF SOUTHEASTERN NEW YORK 23 
difference of opinion concerning the age of the crystalline limestones 
associated with the gneisses in Sussex county. Wanuxem and Keat- 
ing,*’ Kitchell,**® Cook,*® Britton,°° Dana,” and Williams,’* believed 
the crystalline limestone to be Precambrian in age and not related to 
the blue Cambrian limestone of the Kittatinny valley, whereas 
Rogers °° and Nason “* declared the crystalline limestones of Sussex 
county to be metamorphosed Cambrian blue limestones. Kemp and 
Hollick °° described the northward extension of this belt of closely 
involved blue and white limestone and concluded that the white 
crystalline limestone of Orange county, New York, and that of 
Sussex county, N. J., were equivalent and both were metamorphosed 
blue Cambrian limestone. 
Westgate,°° however, believed that the crystalline limestone of 
Jenny Jump Mountain was distinct from and older than the blue 
Cambrian limestone; his conclusions were substantiated and the age 
of the white crystalline limestones definitely proved to be Precambrian 
by the very careful work of Wolff and Brooks *’ who recognized 
fault-relations and realized that “the white limestone was faulted 
over and against the blue” (p. 446). A very careful study of the 
structural features of the gneisses of the Highlands of New Jersey 
convinced Spencer °° of their igneous origin. Spencer recognized 
three types of gneisses ; two of these are intrusive into the limestone, 
and the third, while not found intruding the limestone, was thought 
to be intrusive into the other two gneisses. Pegmatite was found 
47 Vanuxem, Lardner, and Keating, W. H. On the Geology and Minera- 
logy of Franklin, in Sussex County, N. J. Jour. Acad. Nat. Sci. Phila., v. 2, 
pt I, p. 277-88. 1822. 
48 Kitchell, William. Second Annual Report of the Geological Survey of 
New Jersey, for 1855. 
49 Cook, G. H. The Geology of New Jersey, Newark, 1868; idem, Annual 
Rep’t State Geol. N. J., 1873, p. 18-19; idem, Annual Rep’t State Geol. N. J., 
18835D. 27-77. 
50 Ann. Rep’t State Geol. N. J., 1885, p. 36-55, and 1886, p. 74-112. 
51 Dana, James D. Amer. Jour. Sci., 3d ser. 42: 70-72, I8ot. 
52 Williams, H. S. Amer. Jour: Sci, 3d ser. 47: 401-2. 1804. 
53 Rogers, H. D. A Final Report on the Geology of the State of New 
Jersey, p. 12-22, 36. 1840 
54 Nason, F. iby Aaa Rep’t State Geol. N. J., p. 31, 1889; idem, Annual 
Rep’t State Geol. N. J., p. 25-50, 18900; idem, Amer. Geol. 14: 163. 1894. 
55Kemp, J. F., & Hollick, Arthur. The ‘Granite at Mounts Adam and 
Eve, Warwick, Orange Co., N. Y. and Its Contact Phenomena. Annals N. Y. 
Acad. Sci. 7: 638-54. 1892-04. 
56 Westgate, L. G. The Geology of the Northern part of Jenny Jump 
Mountain, in Warren County, New Jersey. Annual Rep’t State Geol., Geol. 
SAV. ING Joy SDs AO) Llskors, 
57 Wolff, i E. & Brooks, A. H. 18th Annual Rept U. S. G. S., pt II, 
1896-07 ; Washington, 1898; p. 425-57. 
58 Spencer, A. C. Annual Rep't State Geol. N. J. for 10904, p. 161-86, 
247-53. Also Mining Magazine, v. 10. 1904. 
