Abstract
In the study of diatoms, bogs furnish an excellent record of diatom flora during the post glacial period. As a result of the Late Wisconsin glacial activity in Northern Indiana was dotted with numerous lakes, many of which are of the kettle-hole type and have become extinct due to deposition of marl and peat. In many bodies of water where diatoms are present, a portion of this sedimentation is composed of the silicified walls of the diatom cells which remain unaltered after the death of an organism. Thus diatom become deposited and preserved in stratigraphic order.