1 68 A NATURALIST IN THE GREAT LAKES REGION 



portions have not yet been invaded by plants. A Httle farther 

 back are interdunal ponds stocked with Chara; then come others 

 with such plants as Myriophyllum and its associates, all forms 

 with finely dissected leaves. These plant populations are similar 

 to the zones shoreward from the bare-bottomed area in shallow 

 lakes. So the successively older dune ponds are comparable 

 to the successive zones of plant and animal forms in the filling 

 inland lakes. The older ponds, if good-sized, will naturally 



FIG. 175. Interdunal swale of the first type 



themselves contain several zones, though smaller ones may be 

 completely occupied by the bulrush stage, the cat-tail stage or 

 by similar plants characteristic of some one zone of the larger 

 filling pond. 



The very new pond in the dune region is but a recent cut- 

 off from the lake. Its bottom is sandy; no plants have as yet 

 secured a foothold. There are present a few fish that find its 

 quiet waters good places to lay their eggs; these must find access 

 by some channel connecting with the lake. The fish commonly 

 found in such a pond include the pike, the red horse, the Cayuga 



