Ashley prepares to dive into the Giant Springs; from a fracture in the Earth's limestone, water flows upward at a force of 300 pounds per square inch, discharging 156 million gallons per day. William Clark discovered this June 18th, 1805, "we proceeded on...to the largest fountain or Spring I ever Saw. and doubt if it is not the largest in America Known, this water boils up from under th rocks near the edge of the river and falls imediately into the river 8 feet and keeps it Colour for 1/2 a mile which is emencely Clear and of a bluish Cast..." (sic).

We enjoyed the astonishing Great Falls at high water flow as described by Meriwether Lewis on June 14th, 1805 "...hearing a tremendious roaring above me I continued my rout across the point of a hill a few hundred yards further and was again presented by one of the most beautifull objects in nature, a cascade of about fifty feet perpendicular streching at right-angles across the river from side to side to the distance of at least a quarter of a mile...the water decends in one even and uninterupted sheet to the bottom wher dashing against the rocky bottom rises into foaming billows of great hight and rappidly glides away. hising flashing and sparkling as it departs the sprey rises from one extremity to the other..."(sic).