The bedded or stratified rocks of the Connecticut Valley vary greatly, from the coarse bouldery deposits in Mount Toby to the fine-textured, red and black laminated beds at Whittemore’s Ferry. Conglomerate, arkose, graywacke, shale and even limestone are represented, but there is little true sandstone. Sandstone is an even-textured, granular rock, most commonly composed of cemented quartz grains. Its uniformity of grain-size and composition reflects prolonged weathering of the original rock and good sorting of the fragments as they were transported to their new resting place. The sequence of exposure, transportation and deposition was too rapid in the ancient Connecticut Valley to permit appreciable decay and sorting; hence sandstones are absent. Limestones and salt beds are likewise rare, but the metamorphosed limestones which are found in the western highlands and in the Berkshire valley demonstrate that limestone-forming processes played a significant, if intermittent, part in the history of the region. CONGLOMERATE is consolidated gravel. Pebbles and boulders of all sizes are packed together by the stream which was moving them, and the spaces between the larger fragments are filled with the sand that settled in from the stream bed. The entire mass is cemented by silica, limonite, carbonates or some other substance deposited by percolating ground-water. The Devil’s football near the Mount Holyoke House is a famous piece which was dislodged from the hillside above; and excellent specimens may be collected on Mount Toby, on Mount Sugarloaf, and in the cut at Mount Tom Junction. ARKOSE resembles conglomerate, but the individual grains consist of mineral fragments, among which reddish feldspar is prominent. Quartz and mica may be present, too; and all the pieces are characteristically angular, commonly ranging from ¹/₁₆ to ⅛ inch in size. The rock is red and crumbles easily. Beds of arkose alternate with conglomerate on the steep sides of Mount Sugarloaf. GRAYWACKE is light to dark gray in color, and the fragments composing it are sand size pieces of older rocks. A few mineral grains, such as quartz, may be present, but mica is rare. Graywacke occurs interbedded with arkose in some parts of the valley. SHALE is a thinly laminated sediment composed of microscopic quartz, feldspar, mica and kaolinite grains. Most shales in the Connecticut valley were deposited as muds in old lake beds. Some are red and record ephemeral pools, but others show from their black color, their coal layers, and their fish skeletons, that the water bodies in which they accumulated remained in existence for a comparatively long time.