emerging from beneath that secondary along its south-eastern margin? We will not, however, contend for the name. It is sufficient for our purpose to state, that the sandstone so abundant in all the principal ridges accessory to the Alleghany on the east, has the character of a rock belonging to the transition class of the Wernerians; that is, its {330} strata have a somewhat regular dip and inclination; it contains no beds of bituminous coal, though many of anthracite, and few organised remains. Near the summit of the ridge called particularly the Alleghany, the change to secondary begins to appear. Without the interposition of any other stratum, and without any sudden change of features, the strata of sandstone become nearly horizontal, assuming gradually all the characters of secondary rocks. About one mile west of the summit of the Alleghany, on the road from Philadelphia to Pittsburgh, the first indications of coal are observed. Descending into the vallies, the transition strata again emerge to the light. The same thing happens in the case of Coatskill and other mountains west of the Hudson, their basis being of transition, and their summits crossed with secondary. The horizontal sandstones connected with the depositions of coal occurring along the Ohio from Pittsburgh to the confluence of Green river, assume various characters,[97] and often support extensive formations of compact limestone. FOOTNOTES: [79] The Report from which these observations are extracted was drawn up at Smithland, Kentucky, in January, 1820, soon after the return of the exploring party from the Rocky Mountains. Since that time, opportunities have been wanting to supply the deficiency of study and comparison, for which that place, remote from all collections of books and minerals, did not afford the means. We may be allowed to mention these circumstances in extenuation of our apparent neglect of many recent innovations in geology, and of some late works, with which we had not the opportunity to be acquainted.--JAMES. [80] Lewis and Clarke's History, vol. i. p. 83. Philadelphia, 1814.--JAMES.