During the latter part of the Ice Age, the Wabash Valley drained thousands of square miles of the Wisconsin glacier and served as the main sluiceway for immense volumes of glacial meltwater. Coarse sand and gravel from glacial outwash were deposited across the sluiceway until it was filled from rim to rim. At the close of glaciation, the catastrophic outburst of Glacial Lake Maumee, known as the Maumee Torrent, most directly shaped the modern valley by filling it from wall to wall with frigid, rushing meltwater for a few weeks, stripping away most of the glacial outwash, and eroding the valley floor into the Silurian bedrock visible today. Because of this, this reach of the Wabash River is an underfit stream, appearing far too small to have carved the massive valley through which it flows. During the last glaciation, the Wabash River followed the former axis of the Erie Lobe Glacier, while major tributaries occupied the margins of the last glacial retreat. The post-glacial watershed initially included the St. Joseph and St. Mary's Rivers, but drainage through the St. Lawrence Seaway and eastern Great Lakes later developed and led to their capture by the Maumee River. The strategically important Three Rivers confluence was then formed, later becoming Fort Wayne and establishing the eastern continental drainage divide. Called Wah-Bah Shik-Ki by Miami Indians, meaning water over white stones because of the limestone river bottom, the Wabash is 475 miles long, is the longest free-flowing river east of the Mississippi River, drains 73 of Indiana's 92 counties, is home to nearly 400 species of wildlife, and was created by the Maumee Torrent 14,000 years ago.