Background. Aseptic meningitis is an illness characterized by serous inflammation of the linings of the brain (i.e., meninges), usually with an accompanying mononuclear pleocytosis. Clinical manifestations vary, with headache and fever predominating.
Lake Superior 1  ... is the largest freshwater lake in the world by surface area and the third largest by volume (Lake Baikal in Siberia and Lake Tanganyika in East Africa contain more water). 2  could hold all the water in the other Great Lakes, plus THREE MORE Lake Eries. 11,000 years ago: Glacial Lake Duluth, the precursor to Lake Superior, forms as the ice sheet retreats northeastward. 2  The lake's torrential outflow near present-day Duluth carves the St. Croix River Valley and feeds the Mississippi River.
HOW TO SEARCH FOR THE ELUSIVE LAKE SUPERIOR AGATE. Although the information below has been compiled to help those in the upper mid-west to search for Lake Superior agates, the same information is relative to agates in other locations. Most Lake Superior agates formed in a rift zone approximately 1.2 billion years ago.