Excavation

Excavation. . Excavation , When the preserve was created, only the easternmost 35 feet of the grooves were exposed. Much of the grooves were filled with till, a mix of small and large sediments deposited directly by a glacier. On top of the till, operators from the nearby quarry had piled on soil and other material., Excavation operations began in 1971 to uncover the hidden grooves. Most of the excavation work was done with a backhoe, but shovels, picks, air spades, and even brooms were used for the more delicate work., The total exposure now measures 396 feet in length, with a maximum depth of about 15 feet, and a width up to 34 feet., Glacial Erratic , Where did this huge rock come from? It is very different from the limestone that makes up the glacial grooves. This large boulder is called a glacial erratic, which is a name given to any stone that was moved a long distance by a glacier, then was left behind as the ice melted away., Take a look at the nearby glacial erratics, It is likely that these rocks helped create the Glacial Grooves. This particular rock was carried hundreds of miles from Canada by ice!, Look Around , Erratics can be any size, and any of the three major rock types (igneous, metamorphic, or sedimentary.), See if you can find other unusual, erratic rocks nearby.