QUATERNARY LAKES IN THE MISSISSIPPI BASIN 485 



Fig. 2. — Part of Madisonville, Ky., topog. sheet, U.S. Geol. Survey, showing 

 beach of extinct Green Lake (named from Green River which now drains the lake 

 bed) and an "island hill." The thickness of the lake deposit here is about 30 feet 

 and the surface 381 to 385 feet above sea. The "island hill" is one of many peculiar 

 partly-buried hills which rise sharply from the flat surface of the material deposited 

 around them so that they bear a strong resemblance to islands rising above a water 

 surface. The beach ridge shows well in the topography between Philips' store and 

 the McLean County line. 



