While Dr. Dwight emphatically rejects the "transportation theory," he imagined he had solved the difficulty in his suggestion "that the cultivation of the land had brought up the seeds of a former forest, within the limits of vegetation, and given them an opportunity to vegetate." But the utter absurdity of this theory may be demonstrated by any one inside of two years, by placing hickory nuts, in different soils, at a depth to which an ordinary plough-point would reach in cultivation; and then, at the end of the second year, examining those that did not germinate the first year. The commonest observer of a hickory forest knows that if the fallen nuts do not germinate the first year, their vitality is utterly and hopelessly gone. It makes no difference whether you leave the nuts on the ground where they fall, or place them one inch or twenty inches beneath the soil, the result will be the same. At the end of two years, you can pulverize them between thumb and finger almost as easily as so much dried loam. The idea of deriving a new forest from such nuts, is hardly less absurd than that of emptying the Egyptian catacombs of their old mummy-cases, in the expectation of seeing a race of Theban kings stalking the earth as before the foundations of either Carthage or Rome were laid. Dr. Dwight was a very close and accurate observer of nature, and suffered few of even the minor points of detail to escape him. In the same work, as well as in the same connection, he gives an account of another forest, which he supposes sprang spontaneously from "the seeds of an ancient vegetation." He says: "A field about five miles from Northampton (Mass.), on an eminence called 'Rail Hill,' was cultivated about a century ago (_circiter_ 1720). The native growth here, and in all the surrounding region, was wholly oak, chestnut, etc. As the field belonged to my grandfather, I had the best opportunity of learning its history. It contained about five acres, in the form of an irregular parallelogram. As the savages rendered the cultivation dangerous, it was given up. On this ground there sprang up a grove of white pines, covering the field and retaining its figure exactly. So far as I remember, there was not in it a single oak or chestnut tree;" and he adds, "_there was not a single pine whose seeds were, or, probably, had for ages been, sufficiently near to have been planted on this spot_." He supposes, however, that the "seeds" (pine cone chits) had lain dormant for ages before cultivation brought them up "within the limits of vegetation."