GEOLOGIC INFLUENCES ON BENEDICT ARNOLD'S MARCH TO QUEBEC, 1775

In 1775, Benedict Arnold proposed an attack on British held Quebec, Canada, advocating a route up the Kennebec and Dead Rivers in Maine, down the Chaudière River in Quebec, and crossing the St. Lawrence River. Using inaccurate maps, Arnold estimated completing a distance of 280 km in 20 days. In addition to hasty planning, poor boat construction, and bad weather, geology significantly influenced this historic event.

Arnold's ships entered the Kennebec at dawn on 20 Sept 1775, and soon encountered the Chopps, a swift flowing constriction at Merrymeeting Bay, confluence of the Kennebec and 7 other rivers. Beyond the Chopps, head tide of the Kennebec was easily reached at Fort Western and bateaux were loaded. Four divisions then left for Quebec on 29 Sept.

The Kennebec presented four portages around falls over exposed Paleozoic metamorphic rocks. Portages occurred at Ticonic, Skowhegan, Norridgewock, and Caratunk Falls. Beyond Caratunk Falls, the expedition left the Kennebec at Carrying Place Stream heading west.

Great Carrying Place is a 21 km portage that avoided an impassable section of the Dead River. Besides length, a 365 m change in elevation existed, with 240 m occurring in the first kilometer. Portage took 5 days and 5-7 trips for each bateau and traversed quagmire spruce bogs.

Reaching Dead River (17 Oct), easy travel occurred until a hurricane struck (21 Oct). Associated rain caused a 3 m rise in the river. Pressing on, bateaux, supplies, and food were lost trying to pass raging waters at Shagadee Falls, arriving at Chain of Ponds on 24 Oct. A 13 km portage over Height of Land via Chain of Ponds was necessary to reach Lac Megantic, headwaters of the Chaudière. Part of the group became lost in swamps around Spider Lake and one division turned back, the remainder regrouping on 3 Nov.

From Lac Megantic (335 m), the Chaudière drops 180 m in 80 km in a series of continuous rapids with several large falls. Without scouting, these cost the expedition many bateaux and much provisions. Passing Grand Falls of the Chaudière, the expedition re-supplied itself and on foot 550 troops reached Quebec City (14 Nov).

Arnold's short venture had turned into a grueling ordeal of 640 km lasting 2 months. Quebec was finally attacked during a snowstorm and resulted in defeat (31 Dec). Arnold was promoted to Brigadier General and the March to Quebec is regarded as one of history's greatest military logistical operations.