5. Argillaceous Slate rests on quartz on Stone Hill, and is also found low down in the valley connected with limestone. It constitutes the hill (P) connected with the Taconick range, and also Northwest hill, (Q) whose base is compact limestone. A few miles north, this slate is distinctly marked, and in about 12 miles, forms hills of roof slate in Hosack, New-York. It is annually carried in large quantities to Albany. On the first-mentioned hill, it contains some talc.
6. Aluminous slate. This is found in argillaceous slate, in Pownal, 5 miles north, at the base of a hill east of the Hoosack. It is used to set colours.
7. Chlorite. In rounded masses, generally with quartz, scattered through the valley in Williamstown, and found at an elevation of some hundred feet on the hills of the Taconick range. Chlorite slate has already been mentioned as occurring on the same range.
8. Rubble Stone. In rounded masses through the valley.
9. Compact Limestone. In several places low in the valley. Near the college it is white and deep gray. In the veins of the latter, talc is diffused in all directions. It contains silex, often from 3 to 15 per cent., and sometimes gives fire with steel. In some cases it is earthy. On Green River, one and a half mile south of the college, it lies in thin strata, which are divided by seams into very regular rhomboidal plates of various sizes. On some scattered fragments on this river, are found carbonate of lime in crystals, with pieces of white feldspar. On West Brook, this gray limestone is traversed by a vein of quartz, containing sulphuret of iron. The strata of this rock are almost invariably inclined to the east. A coarse soapstone is found in the limestone near the college, and a vein made up of brown argillaceous slate, soapstone, quartz, and sulphuret of iron, passes through it. This limestone appears to be very different from that at the base of Saddle Mountain, and from that which yields the marble of Berkshire county. It may still be primitive, but primitive compact limestone.
10. Granitell of Kirwan, Quartz, and Feldspar. This aggregate forms extensive strata at the east base of Stone Hill. The feldspar is diffused in grains through the quartz, and sometimes crystalline, forming porphyritic quartz. This aggregate is often compact and very hard, but frequently it is porous and hard, forming good millstones. Sometimes the quartz appears in such fragments, that the stone resembles breccia.
11. Black Tourmaline. In beautiful small six-sided prisms, in scattered pieces of mica slate at the base of Stone Hill.
12. Amianthus. Only a small specimen, attached to argillaceous slate.
13. Bitter Spar. On compact limestone at West Brook. Some of the crystals are rhomboids, and some appear to be the half of rhomboids split through their longer diagonal.
14. Jasper. The common brown or red, and black, in small rounded masses, and also a piece of variegated or striped jasper.