1 50 Classes of Rocks. 



granular limestone. Varieties. Translucent, Snowy Mount- 

 ains in Wallingford, Vt. Yellowish, most common. Ferru- 

 ginous, Bennington, Vt. Pittsfield, Mass. Contents. Hae- 

 matite, in Dalton, Mass. three miles south of the village. 

 Manganese, in Bennington, Vt. 



6. Granular Limestone. 



Divisions. Compact, Stockbridge, Mass. Sandy, west 

 side of Pittsfield, Mass., on the Albany stage road. Varieties. 

 Statuary Marble, Stockbridge, Mass. Dolomite, Barrington 

 and Sheffield, Mass. Milford, Conn. Contents. Tremolite, 

 Canaan, Conn. Serpentine and chromate of iron, Milford, 

 Conn. 



II. Transition Rocks. 



7. Argillite. 



Divisions. Clay Slate, Williamstown Mountain Range, — 

 the bed and banks of the Hudson. Wacke Slate, overlying 

 the clay slate, most of the way from Massachusetts line to 

 three miles west of Cohoes Falls in New York. As this 

 slate takes the same inclination with the clay slate, and dif- 

 fers widely from the horizontal (or 1st) gray wacke, and u.s 

 their meeting can never be ascertained, I have presumed to 

 join them. Varieties. Chloritic. Both of the divisions are 

 often colored green by the chlorite in Rensselaer county. 

 Roof Slate. That which splits freely into roofing slate, Hoo- 

 sick, Chatham, N. Y. Water Gap of the Delaware River, Pa. 

 Glazed Slate, banks and bed of the Hudson from Fort Mil- 

 ler to near Newburgh, Water Gap of the Delaware. Chlo- 

 ritic, red and purple, varieties frequently occur near its junc- 

 tion with the primitive rocks. Contents. Silicious Slate, 

 nearly black, and of different shades of green, in the glazed 

 variety at Troy and a few miles below Albany, in extensive 

 beds. Basanite, in the glazed slate, near Troy and Albany. 

 Anthracite, in small quantities, near Troy. Striated quartz, in 

 the cleavages of the glazed variety, in a kind of sheet, con- 

 nected with an unascertained green, hard, substance, resem- 

 bling serpentine. Mrs. Griffith's account of Disbrow's 

 method of boring for water, presents facts which seem to 

 make the argillite the great repository of carbonated waters. 

 The borings at Ballston and Albany, about forty miles apart, 

 are made in the same layers of argillite ; and carbonated 

 water is found in both places. 



