extensive surface :--a collection ought therefore to furnish specimens of the most characteristic varieties ;--and t/?e most splendid specimens are, in general, not the rt?st strict/re. Where several specimens are taken in the same place, a series of numbers should be added to the note of their locality. 5. One of the most advantageous situations for obtaining spocimens, and examining the relations of rocks, is in the sections afforded by cliffs on the seashore: especially after recent falls of large masses. it commonly happens that the beds thus exposed are more or less inclined; and in this case, if any of them be inaccessible at a particular point, the decline of the strata will frequently enable the collector to supply himself with the specimens he wishes for, within a short distance. Thus, in the subjoined sketch, which may be supposed to represent a cliff of considerable height,--the observer being situated at a, the beds b, c, d, though inaceeesible at that place, may be examined with ease and security, where they successively come down to the shore, at b'? c', and d'. 6. To examine the/nter/m' of an unknown country, more skill and practice are required: the rocks being generally concealed by the soil, accumulations of sand, gravel, &c., and by the vegetation of the surface. But the strata are commonly disclosed in the sides of ravines,--in the beds of rivers and mountain-streams; and these, especially whexe
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