THE 



JOURNAL OF GEOLOGY 



JANUARY-FEBRUARY, 1904 



GEOLOGY OF MONADNOCK MOUNTAIN, NEW 

 HAMPSHIRE.^ 



CONTENTS. 



A. Description of Monadnock. 



B. Rocks of Monadnock Area. 



1. Andalusite schist. 



2. Fibrolite schist. 



3. Quartzose mica schist. 



4. Rusty, graphitic mica schist. 



5. Granite. 



a) Occurrence in lobes. 



b) Inclusions in. 



c) Alternation of, with schist along the border. 



d) Pegmatite in. 



(?) Relation of, to schist. 



C. Age of These Rocks. 



D. Attitude of the Schist in the Mountain. 



E. Jointing of the Schist. 



F. Two Periods of Metamorphism Indicated in the Schist. 



G. Reason for the Survival of This Mountain. 



Monadnock, situated in southern New Hampshire, is of 

 special interest to geologists because it was selected by Professor 

 Davis as a type of the isolated, residuary peaks that may be found 

 rising above a base-leveled land surface. This mountain rises 

 3,166^ feet above mean sea-level and about 2,000 feet above the 

 surrounding peneplain, the plateau of southern New England. 

 At the first glance the mountain may appear, from its representa- 

 tion on the Topographic Map, as a regular, single peak ; but, on 



^Monadnock is considered in the Geology of New Hampshire, No\. II, pp.24, 

 S03, 639. This area, with a section through the mountain, is represented on the fourth 

 sheet of the geological map in the atlas accompanying the same. 



^From the Topographic Map of the U. S. Geological Survey. 

 Vol.XII, No. I. I 



