The following minerals, found in the region above named, were either omitted in the former list, or have been noticed since that was made out.
Bog-iron Ore. In Greenfield and Warwick.
Hornstone. Rare; in Deerfield and Conway.
Silicious Slate. In rolled pieces, on the banks of Deerfield river; not abundant.
Basanite, or Lydian Stone. Same locality.
Augite. In an aggregate of greenstone, quartz, and calcareous spar, in the greenstone range, Deerfield. Colour black, and the crystals usually imperfect, or broken.
Staurotide. In mica slate, Northfield, one mile east of the village, on the turnpike to Boston. The crystals observed were six-sided prisms. The same rock contains reddish garnets.
THE LEVERETT RANGE OF GRANITE.
This name is given to a granite range that emerges from the puddingstone near the centre of Amherst, and extends northerly, with some interruption, nearly thirty miles, through Leverett and Montague to Northfield. And, indeed, there is some reason to suppose that it again appears to the north of Northfield. The range is widest in Leverett, where its breadth is more than a mile. It is noticed in the "Remarks," No. 2, Art. I, of this Journal, and may be seen on the section accompanying that communication. But on further examination it has been found to be more extensive than was supposed. The texture of the rock is coarse. Plates of mica, 3 or 4 inches across, are common in it; and one specimen of a beautiful blue feldspar, the fragment only of a crystal, measured in one direction 8 inches.
Two circumstances in this range give it an interest in the eye of a geologist. The one is its proximity to sandstone and puddingstone; and the other, its small elevation in comparison with the surrounding rocks of later formations. In some places no other rock could be found lying between the granite and puddingstone; though the soil prevented my observing whether there is an actual contact. But in general there is a stratum of mica slate a few rods wide between these rocks, and not unfrequently gneiss lies between the mica slate and granite.