INTRODUCTION — THE OCCURRENCE OF GRANITE IN MAINE. 
By George Otis Smith. 
GEOGRAPHIC DISTRIBUTION. 
Areally,- granite is perhaps the most important rock in Maine. 
Slates, schists, sandstones, and limestones of various types occur in 
the different sections of the State, but the mountains and hills of 
the interior and the islands and headlands of the coast for the most 
part all exhibit slopes and cliffs of massive granite. Even where the 
exposures are of other rock varieties the notable abundance of gran- 
ite dikes and quartz veins indicates the presence of granite at no 
great distance. Not only is this rock most conspicuous, but its impor- 
tance in both the geology and the industry of the State can hardly be 
overestimated. 
The areal distribution of the granite is somewhat irregular, as may 
be noted on the map accompanying this report (PL I). Three gen- 
eral granitic regions may be distinguished for convenience of descrip- 
tion — that of the western tier of counties, that of the eastern part of 
the State, and the Mount Katahdin area, in the north-central portion 
of the State. In addition to these larger districts there should also 
be mentioned three small areas in Lincoln, Kennebec, and Somerset 
counties, which are intermediate in position between the three main 
regions. 
The granitic areas of the western group are not widely separated, 
and the largest of these areas as outlined on the map is not all 
granite, although, as will be explained in a later paragraph, the 
intrusive granite forms the larger part of the rock exposed within 
these limits. The northernmost of these granite masses is exposed in 
the elevated country which forms the divide between the Chaudiere 
drainage oil the Canadian side of the international boundary and 
the headwaters of Androscoggin and Dead rivers in the northern part 
of Franklin County. South of this is a much larger area of granite, 
extending from the western part of Somerset County across Franklin 
into Oxford County and including prominent peaks, like Mount Big- 
elow and Saddleback Mountain, as well as the rugged country south 
of the Eangeley Lakes. 
South of this is a large, irregular-shaped area of metamorphic 
rocks — gneisses and schists — more or less thoroughly impregnated 
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