THOREAU'S OBSERVATIONS ON THE GEOLOGY OF THE NORTH MAINE WOODS

Henry David Thoreau made three trips to the North Maine woods; in 1846, 1853, and 1857. On each trip he travelled from Boston to Bangor by steamer. On his first trip he travelled up the Penobscot with loggers and rivermen and camped near the mouth of Abol Stream. He made a partial ascent of Mt. Ktaadn, but rather than using the then well-established Abol Slide Trail, he bushwhacked and clambered over boulders well to the east of that trail. While he had read Lyell's "Principles of Geology" and Dr. C.T. Jackson's "Report on the Geology of Maine," he was at a loss to explain "the vast aggregation of loose rocks, they lay as they fell on the mountain side, nowhere fairly at rest, but leaning on each other, all rocking stones." On the mountain he was in "a cloud factory" and was unable to reach the summit, to see the wide tableland, or the great cirques on its east side.

On his second trip he hired a guide from the Penobscot Nation, rode from Bangor to Greenville by stage, and up Moosehead Lake by steamer. Thoreau correctly observed that Mt. Kineo and two others nearby looked much alike, being made of the same rock. He was greatly taken with the idea of water being made to flow from Moosehead Lake to the West Branch and vise versa. Recent heavy rains raised the West Branch two feet, enough to reverse the flow in Lobster Stream, the current carrying them into Lobster Lake, more than a mile without paddling. During millennia of flow reversals, sediment carried into the lake has constructed a delta at the normal lake mouth.

For his last trip, Thoreau again went to Greenville, with another Penobscot guide, now paddling up Moosehead Lake. They stopped on Kineo Island. Quoting Jackson, Thoreau says of the Kineo volcanic rocks, "Hornstone, which will answer for flints, occurs ... where trap-rocks have acted on slate." He does find hundreds of arrow-heads made of this material, a material once widely traded for stone tools. Rather than going down the Allagash as planned, they decide to travel down the East Branch via the Telos Cut. On seeing the Traveler volcanic mountains, Thoreau notes how similar in shape they are to Mount Kineo, with steep slopes resulting from erosion along columnar joints. At Whetstone Falls he notes the eskers along the East Branch, using the Maine term "horseback," but does not comment on their origin. He does recognize the different vegetation pattern when he reaches the inland limit of glacial-marine submergence on the East Branch.