2. A vast quantity of petrified shells are found in limestone, flint, and sandstone, on the same mountains. Mr. Bartram assured me at the same time, that it was incredible what quantities of them there were in the different kinds of stones of which the mountains consist.
3. The same shells are likewise dug in great quantity, quite entire and not mouldered, in the provinces of Virginia and Maryland, as also in Philadelphia and in New York.
4. On digging wells (not only in Philadelphia, but likewise in other places) the [[133]]people have met with trees, roots, and leaves of oak, for the greatest part, not yet rotten, at the depth of eighteen feet.
5. The best soil and the richest mould is to be met with in the vallies hereabouts. These vallies are commonly crossed by a rivulet or brook. And on their declivity, a mountain commonly rises, which in those places where the brook passes close to it, looks as if it were cut on purpose. Mr. Bartram believed, that all these vallies formerly were lakes; that the water had by degrees hollowed out the mountain, and opened a passage for itself through it; and that the great quantity of slime which is contained in the water, and which had subsided to the bottom of the lake, was the rich soil which is at present in the vallies, and the cause of their great fertility. But such vallies and cloven mountains are very frequent in the country, and of this kind is the peculiar gap between two mountains, through which a river takes its course or boundaries of New York and Pennsylvania. The people in a jest say, that this opening by the D—l, as he wanted to go out of Pennsylvania into New York.
6. The whole appearance of the blue mountains, plainly shews that the water [[134]]formerly covered at part of them. For many are broken in a peculiar manner, but the highest are plain.
7. When the savages are told, that shells are found on these high mountains, and that from thence there is reason to believe that the sea must formerly have extended to them, and even in part flown over them; they answer that this is not new to them, they having a tradition from their ancestors among them, that the sea formerly surrounded these mountains.
8. The water in rivers and brooks likewise decreases. Mills, which sixty years ago were built on rivers, and at that time had a sufficient supply of water almost all the year long, have at present so little, that they cannot be used, but after a heavy rain, or when the snow melts in spring. This decrease of water in part arises from the great quantity of land which is now cultivated, and from the extirpation of great forests for that purpose.
9. The sea-shore increases likewise in time. This arises from the quantity of sand continually thrown on shore from the bottom of the sea, by the waves.
Mr. Bartram thought that some peculiar attention should be paid to another thing relating to these observations. The shells [[135]]which are to be found petrified on the northern mountains, are of such kinds as at present are not to be got in the sea, in the same latitude, and they are not fished on the shore, till you come to South Carolina. Mr. Bartram from hence took an occasion to defend Dr. Thomas Burnet’s opinion, that the earth before the deluge was in a different position towards the sun. He likewise asked whether the great bones which are sometimes found in the ground in Siberia, and which are supposed to be elephant’s bones and tusks, did not confirm this opinion. For at present those animals cannot live in such cold countries; but if according to Dr. Burnet, the sun once formed different zones about our earth, from those it now makes, the elephant may easily be supposed to have lived in Siberia.[24] However it [[136]]seems that all which we have hitherto mentioned, may have been the effect of different causes. To those belong the universal deluge, the increase of land which is merely [[137]]the work of time, and the changes of the course of rivers, which when the snow melts and in great floods, leave their first beds, and form new ones.
At some distance from Mr. Bartram’s country house, a little brook flowed through the wood, and likewise ran over a rock. The attentive Mr. Bartram here shewed me several little cavities in the rock, and we plainly saw that they must have been generated in the manner I before described, that is, by supposing a pebble to have remained in a cleft of the rock, and to have been turned round by the violence of the water, till it had formed such cavity in the mountain. For on putting our hands into one of these cavities, we found that it contained numerous small pebbles, whose surface was quite smooth and round. And these stones we found in each of the holes.