Part 6

1. Davis pyrite mine 2. Plainfield manganese mine 3. Lithia spodumene pegmatite 4. Chesterfield tourmaline locality 5. Westfield marble quarry 6. Williamsburg galena vein 7. Hatfield lead mine 8. West Farms lead mine 9. Loudville lead mine 10. Westfield trap quarry 11. Bernardston magnetite mine 12. Gill dinosaur track quarry 13. Mount Toby 14. Sunderland Caves 15. Roaring brook 16. Whittemore's Ferry fish quarry 17. Mt. Sugarloaf 18. Leverett lead vein 19. Notch quarry 20. Northampton granite quarry 21. Titan's Piazza 22. Titan's Pier 23. Ox-bow lake 24. Smith's ferry dinosaur tracks 25. Varved clay pits 26. Mt. Grace 27. French King bridge 28. Mt. Lincoln 29. Pelham asbestos mine

The side road to Roaring Brook leaves the highway east of Mount Toby just north of the old cemetery, and the camp site is on the west side of the Central Vermont Railway tracks. The gray rocks east of the tracks are part of the ancient mountains of Triassic time. Their lofty summits have been worn away by the unceasing activity of weather and running water, and they are now lower than the fans of waste which was discharged from the ancient valleys. Roaring Brook is continuing the work of erosion as it tumbles down from Mount Toby, and frost has loosened the great boulders that lie on the mountainside.

The rock along Roaring Brook is very different from that east of the railroad. It looks a great deal like concrete, with a large assortment of aggregate materials mixed in with the cement. The rock is conglomerate, a mass of coarse stones washed out of the ancient Triassic mountains, deposited at their base and in contemporary stream valleys, and then cemented during the ensuing ages. Many of the pebbles in the conglomerate cannot be found in the old rocks east of the railroad tracks. Actually these rocks change in character at different levels in the uplands of today, and still higher changes which were present in this mountain group during Triassic time have been destroyed, though the record of their presence has been retained in the fragments which compose the conglomerate.

The woodland trail starts up the mountain about 100 yards north of the picnic grounds. The rock beside it is red granite, and the streams of Triassic time flowed over it as they carried the gravel which now makes the Mount Toby conglomerate. The latter first appears about 100 feet uphill, and it is virtually the only rock exposed from this point to the summit. Interspersed sandstone beds disintegrate easily and form quiet pools and basins in the adjacent brook; the pools end a few feet upstream where the water cascades over the edge of the next higher conglomerate stratum.

Mount Toby's summit rises above any other eminence in central Massachusetts east of Ashfield and south of Mount Grace near Northfield. From it the entire country to the south appears low and flat, except for the teeth of the Mount Holyoke Range and the long ridge extending southward from Mount Tom. A slope rises westward from the lowland to meet the edge of the flat New England upland along a line that passes through Shelburne, Conway, Goshen, and Granville. East of Toby this same upland comes so close that it seems but a step across to it.

Many peaks may be seen rising above the New England upland. The one far to the east is Wachusett. Up there to the north-northeast are Monadnock and Mount Grace. Over in the northwest are Stratton and Glastenbury in Vermont, and much nearer and lower is Bald Mountain at Shelburne Falls. Mount Greylock, the highest point in Massachusetts, is almost due west.

The lowland was excavated after the New England upland was elevated, and the main features which distinguish the present landscape were carved out before the end of the Miocene epoch of Tertiary time. The high points which surmount the upland are monadnocks which, like their prototype Mount Monadnock, successfully resisted the ravages of time and New England's changing but rigorous climate.

The Sunderland Caves

The Sunderland Caves are on the northwest side of Mount Toby, just a short walk and an easy climb from State Highway 63. They penetrate a cliff made of conglomerate overlying a shale which accumulated in a Triassic lake. The shale makes the floor of the cave. Joints, forming a right angle with the cliff, break the conglomerate into giant blocks. Frost, smooth shale surfaces, and gravity have caused the two end pieces to creep away from the other conglomerate blocks. The second block from the end has fallen against the end block, forming a high-roofed cave about 100 feet long.

Directly southwest of the lower entrance to the cave, the shale beds are highly distorted along the borders of a trough-like mass of angular conglomerate or breccia, in which boulders up to six feet in diameter are numerous. It is believed to be the record of a Triassic landslide, which avalanched down the mountain front immediately to the east, and into the old lake at the mountain base. It plowed up the clays in the lake bed, carried some of them away, and furrowed the others into the crumpled forms that are clearly visible along the path to the caves.

Mount Sugarloaf

Mount Sugarloaf does not offer Mount Lincoln's retreat from crowds nor Mount Toby's expansive landscape, but it is accessible, and it provides an unrivaled view of the valley between South Deerfield and the Holyoke Range. Its red sandstones and conglomerates rise almost sheer for 500 feet above the Sunderland-South Deerfield road. On the northwest and southeast sides the cliffs are determined by nearly vertical joint planes. During the Ice Age, the southward-moving glacier plucked away the loosely attached blocks facing the South Deerfield and Sunderland sections of the lowland, leaving Sugarloaf as a remnant between the joint surfaces.

The great bites which the meandering Connecticut River has taken out of the lowland are visible east of Sunderland village and south towards Hatfield. Each arc in the edge of the scalloped flood plain is the extremity of a meander loop which the wandering river carved in its bank and then abandoned by breaking through the narrow base or tongue, as it did at the Northampton ox-bow.

An area of low, rolling, sandy hills extends through the pine woods for a mile southward from South Deerfield. The hills are dunes which formed when the Connecticut was picking its channel across the newly exposed and barren bed of glacial Lake Hadley.

The panorama from the west side of Mount Sugarloaf centers about the deep gorge of the Deerfield River. The top of the gorge widens out into a broad strath and affords a glimpse of the more remote upland. The river, emerging from this canyon during post-glacial time, built a huge delta into glacial Lake Hadley, and much of the delta still remains in the terrace which is utilized by the Boston and Maine Railroad as it descends into Greenfield.

Turners Falls

Rushing water has a fascination which was frankly recognized by the highway engineers who made the parking place facing the Connecticut where Route 2 passes along the north side of Turners Falls. Here the river drops over a series of sandstone ledges into a deep and narrow channel at the east base of the trap ridge. Waterfalls are not common in rivers flowing through lowlands; they indicate disturbances of normal stream development and sometimes change in course.

The Connecticut Lowland is old, but its ancient drainage lines were buried by the deposits left in glacial Lake Hadley. The river's present course was established upon these lacustrine sediments, and the inner valley plain is excavated in them. Before entrenchment took place, the south-flowing reach of the river above Millers Falls was deflected westward across the lake plain by the delta of Millers River. It was turned southward once again by the trap ridge near Turners Falls. The river soon cut through the unconsolidated lake beds and found that it was out of its pre-glacial channel. The delta of Millers River had diverted the water from the old rock valley beneath the Montague sand plain, across a rock divide, and into the pre-glacial valley of Falls River. The lake-fill in Falls River has been almost completely removed, and Turners Falls now mark the spot where the Connecticut pours over the bank and into the channel of its pre-glacial tributary. The falls have receded upstream several hundred feet and have cut a deep gash in the Triassic rocks.

Pl. 7. Gorges, in highland and lowland alike, were formed when the rivers were superimposed on coherent rock.

Turners Falls are the product of a series of coincidences. First, the ice sheet and Lake Hadley buried all established drainage lines and forced the streams to adopt new routes over the bared lake bottom. While the lake existed, Millers River threw a weak obstruction in the path of the Connecticut, diverting it to that part of the lowland where one of its pre-glacial tributaries had excavated a slender rock gorge along a fault plane. The river washed the lake deposits out of the gorge, exposed the old bank of Falls River, and was busily cutting a new gorge back into this bank when the dam was constructed and its erosive activities were suddenly arrested.

The French King Bridge

The highway from Greenfield to Athol and Fitchburg passes Turners Falls and crosses the Connecticut River near Millers Falls by way of the French King Bridge. Here the roadway is more than 130 feet above the water level. A picnic ground and parking place at the west end of the bridge make it a particularly attractive place to stop and enjoy the view upstream towards Northfield.

The river occupies a narrow rock gorge for a mile north of the bridge, but at that point the valley widens out. This entire section of the river's course was established on the old bed of glacial Lake Hadley; but after the unconsolidated deposits were washed away, the stream found itself flowing along the weak contact between the Triassic conglomerate on the west bank and the metamorphic rocks of the highlands on the east bank. The river deepened its channel on the weak contact zone and made the scenic cut over which the bridge was built.

The pre-glacial valley lies beneath the sand plain east of the river. Millers River crosses this old valley between Millers Falls and its confluence with the Connecticut, at the east end of the bridge. The rapids at the junction can be traced to the ridge of crystalline rock between the east bank of the present Connecticut and the west bank of the pre-glacial Connecticut. The resistant ledge forms a barrier which Millers River has not yet eroded to its grade.

The conglomerate beds on the west wall of the gorge dip steeply eastward towards the river and end against the crystallines. The beds were originally laid down with a gentle westward inclination. They were tilted steeply in the opposite direction against the crystallines by faulting, which elevated the ranges and pressed down the adjacent basin during Triassic time.

Titan's Piazza and Titan's Pier

Not so long ago, giants and the devil received the credit or the blame for such oddities in nature as rock-masses broken into six-sided columns. Ireland has its Giant's Causeway, and Yellowstone National Park its Devil's Post-pile. Titan's Piazza and Titan's Pier were likewise attributed to activities of the leader of fallen angels and were given names appropriate to such an origin by the early settlers. Dr. Hitchcock, in characteristic fashion, undertook the task of correcting the errors of puritanical psychology by renaming these places during one of the early Mountain Day trips from Amherst College. The entire college body sojourned to the west end of the Holyoke Range to hear the cliffs renamed and their true nature explained.

Devil or no devil, those huge columns had a hot origin. The dark rock in them is part of the main lava sheet which stretches across the valley in the Holyoke Range and swings southward in the Nonotuck--Mount Tom Range. The lava poured out of a series of volcanoes which were strung out along a fissure about three miles to the east, and the molten mass had a temperature of 1200° to 1300° C. The hot lava radiated its heat to the sandstone below and to the air above; and, as it cooled, it contracted like any other substance. The shrinkage was so great that series of cracks formed in regular pattern, with each crack perpendicular to the cooling surface. The stresses producing the fissures were equal in all directions and would have made circular cracks and cylindrical columns; but cylinders have non-cylindrical spaces between them, and the pattern in which the columns are most nearly cylindrical and yet completely occupy all space is hexagonal. So contraction broke the lava into hexagonal columns perpendicular to the cooling surface. The columns are parallel where the lava floor is regular but are curved or radial where the floor is rolling.