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nature of their materials. Can it be be-lieved, that the unconsolidated sand andmarl of Alum bay, now vertical, has beenvertical from the beginning ? In the neigh-bourhood of Bristol, two series of beds,similar in character, but differing materiallyin respect of age, occur in very differentpositions ; the strata of old red are nearlyvertical, those of the newer red nearly ho-rizontal ; is it not highly probable that theywere in the first instance both horizontal ?« It is impossible,” says Mr. Aikin a , speak-ing of a rock in Shropshire , “ that a bed“ of sandstone, and much more of clay,« marl, or mud, as it no doubt was in its“ original state, should have been dispos-“ ed on a plane, at an elevation of from« 30° to 40°, in such a manner as to con-“ stitute an extensive stratum of a uniform« thickness, and that hardly exceeding a“ foot for a depth of at least a hundred“ feet.”
“ The Tubulites, which pierce the“ marl at Steeraway, lead to the same« conclusion : some of these, twelve inches