THE PELHAM AND WILBEAIIAM AREA. 47 



the fresh granular quartz is free from fluid pores aud acicular luicrolites. 

 Feldspar is not distinguishable. 



The nearly colorless actinolites are parallel, aud contain large, rounded 

 grains, common also in the quartz, which are strongly refringent and polarize 

 brilliantly; they may be zircon. Other grains clustered along the actinolite 

 crystals seem to be epidote. 



4. Actinolitc-qnartzite from east bluff of Mount Hygeia, Pelhain. A 

 granular quartz, white and of medium grain, with parallel needles of color- 

 less to aquamarine actinolite. 



In the o-ranular quartz ground the actinolite needles are irregularly 

 an-anged; here and there is a scale of biotite. There are large zircons and 

 microlites inclosed in quartz and actinolite; also grains of titanite. 



SAXONITE AND SERPENTINE IN MONSON GNEISS. 

 THE PELHAM ASBESTOS QUARRY. 



This locality has been long known as furnishing large masses of a 

 hard asbestos, and the mineral has been extensively quarried. 



Its interest from a mineralogical point of view was greatly increased 

 by the discovery in 1869, by Mr. A. B. Kittredge, of corundum in hard 

 nodules in the biotite, which occurs there in great abundance. Later, Pro- 

 fessor Shepard, observing the difficult fusibility of the " asbestos," analyzed 

 it and found it to have the composition of l^ronzite, but gave it the wholly 

 superfluous name asbestite. He also analyzed a tough, black, granular 

 mineral which occurs in large masses in the deeper parts of the several 

 excavations and found it to have the composition of oli%'ine, but named it 

 pelhamine, a name equally supei-fluous, as the mineral is optically as well 

 as chemically identical with olivine, and its black color is due to dissemi- 

 nated magnetite and chromite. 



The pits by which the bed is exposed are scattered for a distance along 

 an eastward-sloping hillside, and as the dip is 40° W., while the strike of 

 the inclosing Monson gneiss is due north, the lenticular mass is exposed 

 by erosion in a plane at right angles to its dip, gi^'ing a length of about 200 

 feet and a greatest thickness of 40 feet. 



This is a great lens or short dike — probably an old volcanic core — of 

 the highly basic igneous rock saxonite, in the highly acid conglomerate 



