25th): "When I wrote you last, I had not been able to procure your memoir on the fossil tree.

I read it, however, immediately after, and was so much pleased with it, that I extracted the most important parts in the _American Journal_, giving credit, of course, to you and to the Geological Society." _Jan.29th_.Chester Dewy, Professor, &c., in Williams College, Mass., writes a most kind and friendly letter, in which he presents various subjects, in the great area of the West, visited by me.
_Chalk Formation_.--"Mr.Jessup, of Philadelphia, told me that he believed you doubted respecting the _chalk_ of Missouri, in which you found nodules of flints.

I wish to ask if this be fact.

From the situation, and characters and uses, you might easily be led into a mistake, for such a bed of any other earth would be far less to be expected, and be also a far greater curiosity." _Petrosilex, &c._--"By the way, I received from Dr.Torrey a curious mixture of petrosilex and prehnite in radiating crystals, which was sent him by you, and collected at the West.

He did not tell me the name, but examination showed me what it was." _Tufa from Western New York_.--"To day, a Quaker from Sempronius, New York, has shown me some fine tufa.