Rocks of Shelburne
Most of Shelburne is underlain by a series of sedimentary rocks, first formed 400-500 million years ago along the shore of a warm, shallow ocean (see Geologic History for more information). The physical features of these rocks hold clues to their original environment, which helps geologists interpret their history. This page gives an overview of Shelburne geology, with a closer look at a few important or interesting rocks and features.
Geologic map of Shelburne
Notice the North-South striped pattern of the map. Most of the rocks in Shelburne were originally deposited in flat layers like a stack of books, but were tilted on their side during the mountain-building events that formed the Green Mountains. Thus, the edges of each consecutive layer appear like a series of stripes, just like a stack of books turned on their end.

The Champlain Thrust, a large fault where a thick block of older rocks was thrust up and over younger rocks, is marked by a toothed red line. Notice that to the west of the fault lies the young Iberville Shale, while to the east lies the much older Monkton Quartzite.

A geologic map shows where different types of rocks occur at the surface of the earth. Different colors mark "formations", which are specific groups or layers of rock that share enough common features to be grouped together, and distinguished from other layers around them. The key to a geologic map is arranged in the vertical order of the rocks, with the lowest (and oldest) rock at the bottom. Red line indicates Shelburne town boundaries. Map courtesy of PLACE program.
Local Rocks