st, 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. I mention it, because you may, in
your travels, be able to see it. He says it covers an acre or more to a
great depth, is burned into excellent lime with great ease, and is very
valuable, as no good limestone is found near them. Some of it is very
soft, like agaric mineral, and would be so called, were it not
associated with beautiful tufa of a harder kind."

_Geology of America_.--"You have explored in fine situations, to extend
the knowledge of the geology of our country, and have made great
discoveries. I congratulate you on what you have been able to do; I hope
you may be able, if you wish it, to add still more to our knowledge."

_Jan. 29th_. Mr. McNabb says: "I have just received a specimen of
excellent pit-coal from Tioga county, Pennsylvania, near the head of the
south branch of the Tioga River, and about twenty miles south from
Painted Post, in Steuben County. The quantity is said to be
inexhaustible, and what renders it of still greater importance is, that
arks and rafts descend from within four or five miles of the mines."

_New Gazetteer of New York_.--Mr. Carter writes (Feb. 5th)
inauspiciously of the course of affairs at Washington, as not favoring
the spirit of exploration. He proposes, in the event of my not receiving
the contemplated appointment, the plan of a Gazetteer of New York, on an
enlarged and scientific basis. "I have often expressed to you my opinion
of the Spafford Gazetteer of this State. It is wholly unworthy of public
patronage, and would not stand in the way of a good work of the kind;
and such a one, I have the vanity to believe, our joint efforts could
produce. It would be a permanent work, with slight alterations, as the
State might u