_Animal Impressions in Limestone_.--"I am much obliged to you for your kind intention of furnishing me with a paper on the impressions in limestone, and I hope you will bear it in mind, and execute it accordingly.
"I have observed the appointment which the newspapers state that you have received from the government, and regret that it carries you so far south,[11] into an unhealthy climate; wishing you, however, health and leisure to pursue those studies which you have hitherto prosecuted so successfully."
[Footnote 11: This is evidently an allusion to St. Mary's, in Georgia, instead of Michigan.]
Professor Frederick Hall, of Middlebury College, addresses me (Jan. 14th) on the same subject. He alludes to my treatise "On the Mines, Minerals, &c., of the western section of the United States;" a work for which our country and the world are deeply indebted to your enlightened enterprise and unrelaxing zeal. Before reading it, I had a very inadequate conception of the actual extent and riches of the lead mines of the West. It seems, according to your account, that these mines are an exhaustless source of wealth to the United States. "I should feel glad to have them put under your superintendence; and to have you nurture up a race of expert mineralogists, and become a Werner among them."
Professor Silliman writes (Jan. 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."