Letter on some points of the Geology of Texas, New Mexico, Kansas, and Nebraska; adressed to Messrs. F. B. Meek and F. V. Hayden. Zurich (Switzerland), October 20th 1858. Dear Sirs: In April last, I received the following letter: Smithsonian Institution. Washington, D. C. March 24th 1858. Dear Sir, Inclosed 1 send you a copy of the Geological results arrived at from an Exploration of the Black Hills of Nebraska. I am quite cer tain it will interest you much and you will do Mr. Meek as well as myself a great favor by securing its insertion in some journal in your country, or in France. Believe me very truly your obedient servant M. Jules Marcon, Prof. F. y, H.AYDEN. Zurich (Switzerland). It was accompanied by the following note from my friend Prof. Spencer F. Baird, assistant-secretary, Smithsonian In stitution : March 24th 1858. My dear Sir, I send a communication from Dr. Hayden which he wishes com mended to your favorable consideration. Yours truly Prof. J. Marcou. S. F. Baird. I accordingly translated your short memoir and procured its publication in the Bibliothique Universelle de Geneve; as it appeared in the National Intelligencer and in Silliman's Journal, I will not reproduce it here. Not having the honor of a personal acquaintance with you, I considered this communication as a proof that, after having opposed my opinions and observations on the Geology of the West, you had changed your views and found that my observations, or hazardous guesses, as they are called in Sil-
