No. 8. Argillaceous chlorite sandstone, consisting of minute grains of quartz, chlorite slate, and talc, united by an argillaceous cement; its colour is yellowish green; fracture uneven; the powder is soft, and feels greasy to the touch; it is destitute of organic remains. No. 9. A loose-grained argillaceous sandstone, thickly interspersed with thin laminæ of talc; its colour is light gray; fracture uneven; texture loose; it is liable to disintegration. No. 10. Argillaceous sandstone, irregularly slatose; its colour is gray, with a tinge of yellow. Nodules of clay ironstone occur in considerable quantities through the mass of rock. No. 11. Fine-grained argillaceous sandstone, composed of quartz and magnesia united by an argillaceous cement. Its colour is yellowish gray, which by the action of the blow-pipe passes into reddish brown. This rock contains great numbers of the impressions of the phytolites. No. 12. Indurated clay; its colour is bluish gray, structure slatose; fracture approaching uneven; hardness inconsiderable. Impressions of small leaves occur in this, but are not numerous; they apparently consist of one species alone. No. 13. Compact argillaceous sandstone; composed of quartz, felspar, and their laminæ of talc, united by an argillaceous cement; its colour is brownish gray. Nodules of clay ironstone occur in considerable abundance in this rock; they are formed by concentric layers, around a nucleus, which is the same in composition as the mass of their bed. Their size varies from that of a nut to an apple. From _Mr. Jessup's_ MS. Report.--JAMES. [PART II][98] _Containing the Calculations of Observations made by Major Long and Lieutenant Swift, on a tour from the Council Bluffs on the Missouri river, westward along the river Platte to its head waters in the Rocky Mountains,--thence southwardly to the head waters of the Arkansa and Canadian rivers,--and down said rivers to Belle Point, performed in 1820, under the command of Major S. H. Long, of the United States' Topographical Engineers._ * * * * * _Note._--The instruments used in making the following astronomical observations, were a portable sextant of 5 inches radius, graduated by the assistance of the vernier to 30˝, made by Cary, London, accompanied by a mercurial artificial horizon with a glass frame, and an excellent patent-lever watch, by Robert Roskell. * * * * * _Camp on the river Platte, at the fording place of the Pawnee Indians, twenty-seven miles below the confluence of the North and South, or Padouca Forks._