tions of their owners. I have never known a whole vessel to be found in a shell-heap. An examination of this pottery, then, it seems would give us a pretty correct idea of the progress of the aborigines in the art of pottery during a period of time corresponding with that of the age of the shell-heaps.
An inquiry therefore into this progress among the builders of the shell heaps necessarily involves a question of time, and is by far the most difficult part of the subject.
In the section of the shell-heap given in the illustration, it will be seen that a stratum of soil six inches in thickness has accumulated since the completion of the mound, and that a similar stratum nearly two feet in thickness occupies a position near the center of the mass, indicating a cessation in the growth of the heap, when it had reached a height of seven feet, for a period of time sufficient for the accumulation of this two feet of soil on the surface of the shell. After this the accumulation of shell begins again, and when it had acquired a depth of three feet it ceased again and this time forever.
Now, we know pretty well how long a period has elapsed since the aborigines ceased to inhabit this region, and although it is possible that there has been no addition to this heap for seventy-five or one hundred years, we know positively that there has been none for the last fifty years. It requires then at least fifty years to accumulate six inches of soil on a shell-heap, and consequently we may be justified in supposing a period of two hundred years to have been necessary for the formation of the central stratum of soil in this mound.
A comparison of the pottery immediately above and below this stratum of soil representing a period of two hundred years ought to give us some idea of the rate of progression made in the arts. And a critical comparison of the different styles of pottery with each other in different portions of the heap should give us a rude idea of the age of the shell-heaps. The object of the present
