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been realized in the eastern portion of the Adirondack area, where 

 the limestone is thinnest. The main problem of the region, the origin 

 of the gneisses, is as yet far from settlement. The tendency is, how- 

 ever, to ascribe to them an igneous origin, and to place them later 

 than the Oswegatchie series, in the areas where they have been most 

 closely studied. 



Jones,' m connection with a description of Tallulah Gorge of north- 

 eastern Georgia, describes the crystalline rocks there occurring, and 

 gives a little sketch map showing their relations. They are called 

 pre-Cambrian. 



Watson^ describes the granitic rocks of the Piedmont plateau of 

 Georgia. Field and laboratory studies indicate that they are not all 

 contemporaneous in origin. Some of them are pre-Cambrian, while 

 others may possibly be later in age. 



Adams ^ describes the Laurentian granitoid gneiss and granite of 

 the Admiralty group of the Thousand Islands, Ontario. The granitoid 

 gneiss is presumably derived by metamorphism from the granite. A 

 large exposure of crystalline limestone on Island No. i8 resembles in 

 all respects that of the Grenville series of the mainland adjacent. 



Parks ■• describes the geology of the Moose River Basin in Canada, 

 including the Moose and Abitibi Rivers, tributary to James Bay. This 

 is an immense triangular area of which the apex is at James Bay, and 

 the base stretches from above Lake Abitibi to a point west of Kabina- 

 kagami. The southern and major portion of this triangular area con- 

 sists of Laurentian gneisses and granites crossed, by bands of Huronian 

 rocks. Along the Abitibi River, Huronian rocks, consisting of 

 altered diorites, pyrites, gray quartz schists, and some soft decom- 

 posed schists occupy the country to the south, extending as far north 

 as the head of the first long rapid on the Frederick House River. The 

 line of contact of this belt crosses the Abitibi below the Iroquois 



' The Geology of the Tallulah Gorge, by S. P. Jones : American Geologist, 

 Vol. XXVII, 1901, pp. 67-75. 



^The Granitic Rocks of Georgia and Their Relationships, by T. L. Watson : 

 American Geologist, Vol. XXVII, 1901, pp. 223-225. 



3 Notes on the Geology of the Admiralty Group of the Thousand Islands, by 

 Frank D. Adams: Can. Rec. of Sci., Vol. VII, 1897, PP- 267-272. 



''Parks, William A.: The Nipissing-Algoma boundary, Eighth Rept. Ont. Bur. 

 Mines, 1899, pp. 175-204, with geological map; Niven's base line, Ninth Rept. Ont. 

 Bur. Mines, 1900, pp. 125-142 ; The Huronian of the Moose River Basin, University 

 of Toronto Studies, Geol. Series No. i, 1900, pp. 35, with sketch map. 



