The gently undulating New England upland stretches off to the north and east for miles. The innumerable hills which compose it integrate to form a horizontal skyline, which suggests a flat erosional plane, originally formed at, or near, the level of the sea. To the northeast Mount Monadnock in New Hampshire rises prominently above the general level, for its extremely resistant rock withstood reduction by weather and water more effectively than the weaker bedrock on every side. The valley lowland begins but three miles to the southwest. The range of hills stretching away like beads on a string is the Holyoke Range. Mount Toby, Mount Sugarloaf, and the Pocumtuck Hills are the prominences in the lowland to the northwest. The lowland was eroded out of the New England upland after the land was elevated far back in Tertiary time, and the disintegrating rock was carried to the sea by the rivers. The hills in the lowland were left where the rocks resisted destruction more successfully than elsewhere, but they only approximate the level of the upland of which they were once a part. Mount Lincoln and the surrounding hills are strewn with boulders. Every slope is dotted with large irregularly shaped rocks, many of which have smoothed facets marred by minute scratches. The boulders were left by the Great Ice Sheet when it melted off New England, and the scratches were made when the ice dragged the boulders over hard rock surfaces. These stones came down from the north, and among them you may recognize types which you have seen in the ledges around Orange and Northfield. Early Pelham settlers found the boulders as much in their way as the trees; so they burned or used the trees, and they piled the stones in long rows to fence their fields. Stone fences characterize all glaciated regions, and here they follow the roadsides for miles, reaching to the edge of the deposits in glacial Lake Hadley. _Mount Toby_ “Let’s go to Mount Toby” usually means to go to the camp ground along Roaring Brook at the east base of the mountain, or to one of the sugar camps on the west slope, or to the Sunderland Caves at the north end. All of these places are worth knowing, but the view from the mountain top deserves at least one trip, and the wood road from Roaring Brook is replete with interesting sights. [Illustration: Pl. 6. _View of the Holyoke Range from Mt. Lincoln._] [Illustration: Fig. 21. _Map showing location of interesting places._]