27 slates, chales and quartzite at about 550 ft. above the sea (anemoid). These dip gently toward the west or south of west, and this is the highest exposure of them in the hill, their upper limit above the slope topping the buttresses and at the lower contact with the diabase being about 600 feet above tide. where we scaled the cliff the diabase sill is about 60 feet thick. This seems to be its thinnest part. The upper sur- fice of the plateau is roughly oval in outline, with its longer diameter running approximately E.-W. for about 300 meters. The surface of the plateau is gently undulating in contour and its highest point is about 710 feet above the sea. Its general slope is slightly to- ward the W.S.W. The side of diabase thickens toward the west and is not less than 100 feet thick at the western end of the butte, when the diabase rests on massive buttresses of the sedimentaries. The effects of chemical weathering and mechanical disintegration are prominent in every direction; oxidation with and without hydration, flaking and round- ing of corners and edges, polygonal cracking on vertical as well as horizontal surfaces, sand and gravel, "desert varnish", carving by wind and wind blown sand (and snow?) Induration of the surface rocks is particularly shown along