One day in the spring of 1820, a singular occurrence took place on one of the upper tributaries of the Mississippi. The bank, some fifteen or twenty feet in height, descended quite abruptly to the stream's edge. Though both shores were lined with dense forest, this particular portion possessed only several sparse clumps of shrubbery, which seemed like a breathing-space in this sea of verdure-a gate in the magnificent bulwark with which nature girts her streams. This green area commanded a view of several miles, both up and down stream.