The city of Cedar Rapids has grown up around a stunning traffic stopper and an amazing example of a glacial erratic. At 140 tons, the Rolling Rock is considered a ‘true’ erratic in that it is a boulder that was carried, in tact from another area by glacial movement during the last ice age. This rock most likely came from the Dighton area about 15 miles north and is considered an erratic because the rock around it (granite) does not match the rock it is made of (a conglomeration).
It is known as the Rolling Rock because Native Americans were said to exact punishment from guilty parties by ‘rolling’ the rock upon the victims’ limbs that had been placed underneath the edges. Until the 1860s, the rock could still be rocked, but was shimmed to reduce additional movement.
In 2008, Massachusetts Governor Deval Patrick signed a bill making the rock the official glacial rock of the commonwealth. It’s about time.