What exactly is a lost lake?
Lost Lakes are part of the Kirk Cluster of points. Early Archaic in age, and mainly found in the the East Central region of the US.
They are named after the type site itself, which is in Limestone county Alabama.
They are broad, deeply corner notched blades made from higher grades of raw chert, and usually possess excellent craftsmanship. They are known as "beveled" points because of the resharpening process, which entailed pressure flaking the left hand side of each face until the point was used up. It produced a rhomboid cross section and gives a distinctive look.
Use- wear analysis shows that they were used as knives.
Here is a reproduction that I knapped.