The glacier s heavy ice crushed fossils or carried them away and covered the land under boulders and gravel. Most of Maine s fossil sites are in northern Maine, in areas of sedimentary rocks. Most fossils found in these sites range from about 345 to 550 million years old. These are generally the shells of marine invertebrates. Some resemble modern clams, snails and corals.
Crinoids are among Maine s most abundant fossils.
They are evidence of the vast crinoid colonies that lived in shallow seas during the Devonian and Mississippian periods. Because these animals look like plants, they are sometimes called sea lilies.