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186 the numerous fucoidal rocks. As to the first question, we must admit that, throughout Campania and the greater part of the Principatas, we cannot, generally speaking, perceive with sufficient clearness the super-position of one system of rocks above the other. Not so in Lucania: there the super-position of the fucoid strata above the Apennine limestone is very evident, and their conditions are notably different. These observations have induced us to maintain, not only that the former were laid down at a subsequent period to the latter, but also, what is still more important, that they belong to two distinct formations. Perhaps the most suitable place for examining these conditions is the Valva Road, along which, from Oliveto to within a few miles of Atella, we never lose sight of the line of contact between the hill of the second series and the mountains of the first. The latter appear to come out from under the hills which lie round their bases; and in some places, as at Fontana della Rose, between Laviano and Muro, the order of the strata which form the hill is clearly seen to rest upon the Apennine limestone. At the same time we can observe the difference of direction and inclination of the strata belonging to the two systems: a discordance which is also manifested in the different topographical aspect of which we have already spoken, and which cannot exclusively depend on difference in mineralogical composition of the rocks. As the strata of clays, sandstones, and limestones with fucoids, in the northern provinces, do not possess any notable difference of composition from those in the southern, nor are the paleontological characteristics at all different, arguing from analogy, we consider them all to belong to the same formation, and are confirmed in this opinion by never having met with any fact which could clearly contradict it. From this difference between the Apennine limestone and the rocks of the second series we are led to infer, as a necessary consequence, that the former must have been displaced before the latter were deposited; and again, these latter rocks being so much inclined is the proof of a second period of elevation. The manner in which the rocks of both series interstratify with each other appears to us sufficiently to declare that the more ancient formations cannot of necessity have been exempt from the disturbing force which displaced the more recent. Of