subject. From what knowledge I have been able to obtain in that department, I am inclined to arrange the secondary class thus: Breccia, compact, or shell limestone; gypsum, secondary sandstone. I leave much, also, for peculiar local formations. A gentleman presented specimens to the Troy Lyceum, from Illinois, of gypsum and secondary sandstone, and informed me that the latter overlaid the former in regular structure. Myron Holly and others have given me similar specimens, which they represent as being similarly situated, from localities in the western part of this State. This secondary sandstone is sometimes more or less calcareous. I believe it is used for a cement by the canal company, which hardens under water. Will you do me the favor to settle this question? On your way to Detroit you may perhaps, without material inconvenience, collect facts of importance to me in reference to secondary and alluvial formations. Anything transmitted to me by the middle of April on these subjects will be in season, because I shall not have printed all the transition part before that time. Have you any knowledge of the strata constituting Rocky Mountains? Is it primitive, or is it gray wacke, like Catskill Mountains? I have said in a note that after you and Dr. E. James set foot upon it we shall no longer be ignorant of it. I intend to kindle a blaze of geological zeal before you return. I have adapted the style of my index to the capacity of ladies, plow-joggers, and mechanics." Prof. Eaton also delivered lectures at Lenox Academy and the Medical College at Castleton, Vt., where he was appointed Professor of Natural History in 1820. He gave lectures and practical instructions in Troy, and thus laid the foundation for the establishment there, as a direct result of his work, of the Lyceum of Natural History; and it is said that in the fall of 1818 Troy could boast of a more extensive collection of American geological specimens than could be found at any other literary institution in this country. The geological and agricultural survey of Albany and Rensselaer Counties, made in 1820 and 1821, by Prof. Eaton and Drs. T. Romeyn and Lewis C. Beck, at the expense of the Hon. Stephen Van Rensselaer, is believed to have been the beginning of such surveys in this country, and was described by Prof. Silliman, in his Journal, as a novel attempt. Next was a geological survey by Prof. Eaton, also at the instance of Mr. Van Rensselaer, of the district adjoining the Erie Canal, the result of which was published in 1824, in a report of one hundred and sixty pages, with a profile section of rock formations, from the Atlantic Ocean, across Massachusetts and New York, to Lake Erie. Governor Seward said of this work, in the Introduction to the Natural History of the State of New York, that it "marked an era in the progress of geology in this country. It is in some respects inaccurate, but it must be remembered that its talented and indefati-
