MILL CREEK. 215 



Such palpably absurd descriptions of animals found 

 in the Delaware are of some interest to the naturalist, 

 in that they open up the question whether, even so re- 

 cently as two centuries, marine forms may not, far more 

 frequently than now, have wandered up the river very 

 near or quite to the termination of the tidal portion of 

 the stream ? 



I have been told by very old men that the common 

 harbor porpoise was seen nearly every year as far from 

 the bay as Bristol and Burlington ; the seal is still no 

 stranger, and a skate was taken near Bordentown in 

 1860, and exhibited in the Trenton markets. These 

 now strictly marine forms can live in fresh water, as we 

 have seen why may not the navigation of the river by 

 steam-vessels, and the general disturbance of its waters 

 by so many means, have driven them oceanward, as the 

 general settlement of the river's shores caused all the 

 larger mammals to retire ? 



Mill Creek is the only running water, I believe, where 

 the pretty water -shield is to be found, except in the 

 mill-ponds scattered at intervals along the valley of 

 Mechen-tschiholens-sipu ; but as the prettiest of mill- 

 ponds is necessarily somewhat artificial, I do not con- 

 sider them, visit them, or feel interested particularly in 

 what I hear of them. 



Of this pretty water-plant, the Brasenia, I gathered 

 a number of floating, delicate leaves, and endeavored to 

 secure the entire stem also, but this was too difficult a 

 task for an August afternoon. The under side of the 

 leaf and the stem are purplish brown, and were covered 



