Schoolcraft'' s Localities, 49 



Chalcedony. — At Point Keewiiweenon, Lake Superior. 

 Imbedded in Amygdaloid, in globular masses from the size 

 of an ounce ball to that of a hen's egg. Also, very plenti- 

 fully, along the shore, more or less abraded. 



Agate. — With the preceding. Imbedded, or detached. 

 All the specimens which I have obtained from this place are 

 onyx agates, consisting of parallel stripes of variously col- 

 oured chalcedony, jasper, hornstone or quartz. They va- 

 ry in size from small nodules, to that of a 32 pound shot. 

 When broken from the rock they present a uniform dull 

 brick red surface, which is worn off from the masses that lie 

 along the shore. I possess the fragments of a single speci- 

 men, that was probably 5 inches in diameter, in which the 

 outer layer, which is yVths of an inch broad, is a light vio- 

 Jet coloured amethyst. 



Mica. — This substance is so generally wanting in the 

 granitic rocks of this region, that 1 had doubted whether 

 we possessed any true granite in this part of the continent. 

 It exists, however, in the granite of the Porcupine moun- 

 tains of lake Superior, in large folia, of a silvery and some- 

 what pearly hue. The specimens brought to me from 

 those mountains, in the course of this season, are connect- 

 ed with a high flesh coloured feldspar, and small masses of 

 common quartz ; and are quite conclusive as to the primi- 

 tive composition of those mountains. 



Clay stone. — On the banks of the river St. Mary's, near 

 the Sault, or Falls of St. Mary, Mich. Ter. It occurs in 

 detached rounded or elongated masses in a kind of clay 

 which is employed for bricks, or it is sometimes found in 

 loose masses along the banks of the river. It assumes vari- 

 ous imitative forms. H. R. S. 



Jidy, 1823. 



Art. IV. — Localities of minerals, communicated by Dr. 

 William Meade. 



Philadelphia, April 9, "i 823« 



Sir, 



Having made an extensive tour 'last Summer to the East* 

 ward, particularly in the States of Connecticut and Massa- 



VoL. VII.— No. 1, 7 



