1884.] NATURAL SCIENCES OP PHILADELPHIA. 191 



Boston Harbor, have a habit of covering themselves with sea- 

 weeds, packing it down snugly above them, as if to avoid observa- 

 tion : and this habit makes them difficult to find." In Clearwater 

 Harbor the white shells, with which the sea-urchins cover them- 

 selves, make a conspicuous object, so that the animal underneath 

 can easily be found. They evidently do not seek concealment 

 from an enemy, as the seaweeds would more effectually accom- 

 plish that object. 



The shell mounds of the west coast are very numerous ; and 

 they indicate the former favorite camping grounds of the Indians. 



The largest accumulation of shells is at Cedar Keys. A portion 

 of that town is built upon the mound ; and great quantities of the 

 material, consisting almost exclusively of oyster shells, have been 

 used in grading the streets. 



Oysters are very abundant and of good size in the vicinity of 

 Cedar Keys, and along the coast as far as forty-five miles farther 

 south. The following small rivers flow into the Gulf of Mexico 

 near the oyster beds : — Wakasassa, Withlacooche, Crystal River, 

 Little Homosassa, Homosassa and Cheeshowiska. 



Near the outlets of these rivers are numerous small islands, 

 too low to be habitable, except when elevated by artificial means. 

 At each river the Indians selected an island for their camping 

 ground, to which they carried oysters ; the shells, in the course of 

 a long time, making large mounds. Human bones, stone imple- 

 ments and fragments of pottery are frequently found among the 

 shells. 



Prof. Wyman, having examined many fresh-water shell mounds, 

 on and near the St. John's River, states in the Memoirs of the 

 Peabody Academy of Science, vol. i, No. 4, 1875, on page 49, 

 that " Stone chips are not common, and were generally found 

 separately, or only a few together ; but in no instance in collec- 

 tions indicating a place for the manufacture of arrow heads or 

 other implements." Such a place for the manufacture of stone 

 implements may be seen on John's Island at the mouth of the 

 Cheeshowiska River. Having visited this island mound several 

 times, the writer has found there at least a half bushel of stone 

 implements, in the various stages of manufacture ; and at the 

 present time many bushels of the stone chips may be seen there, 

 all made of the chert rock referred to above. 



