Figure 13. Bubble Rock, or the Balanced Boulder, is perched precariously on the southeast corner of the summit of the South Bubble, Acadia National Park. Bubble Rock is clearly different from the rocks on which it sits; it is a white granite rather than the pink granite that makes up the Bubbles and the surrounding mountains. It is an example of a glacial erratic, a rock fragment or stone transported by a glacier and deposited at some distance from the source outcrop from where it was derived, and generally, though not necessarily resting on bedrock of a different rock type (Bates and Jackson, 1980). Photo from Maine's Ice Age Trail, Downeast.
Last updated on March 26, 2012