The discoveries already made are encouraging; but vast room is left for the further industry and sagacity of geologists.

This is sufficiently shown by the opposite theories which have been espoused; one of them regarding water, the other fire, as the great agent employed by nature in her work.
"It may well be expected that this hemisphere, which has been least explored, will yield its full proportion of materials towards a satisfactory system.

Your zealous efforts to share in the contributions do credit to your love of truth and devotion to the cause of science, and I wish they may be rewarded with the success they promise, and with all the personal gratifications to which they entitle you." Mr.Jefferson (Ex-President United States) sends a note of thanks (Jan.
26th) in the following words: "It is a valuable element towards the knowledge we wish to obtain of the crust of the globe we inhabit; and, as crust alone is immediately interesting to us, we are only to guard against drawing our conclusions deeper than we dig.

You are entitled to the thanks of the lovers of science for the preservation of this fact." Mr.John Adams (Ex-President United States, Jan.

27th) says: "I thank you for your memoir on the fossil tree, which is very well written; and the conjectures on the processes of nature in producing it are plausible and probable.
"I once lay a week wind-bound in Portland road, in England, and went often ashore, and ascended the mountain from whence they get all the Portland stone that they employ in building.