when most compact, it has quite a liassic aspect in hand specimens; it varies much in colour, however; red, purple, variegated, and nearly white, are to be found. In many places it presents metamorphic characters, and becomes for limited areas, flinty and hard.
A great band of this limestone, extends from around the Terra di Lavoro, southwards to the Gulf of Taranto, from thirty to forty miles wide on the west side; it winds about, forming the summits of all the hills that rise out of the level bed of tufa, that surrounds Naples, and then stretches away northward in a still wider band to the eastward, and a narrower one to the westward, sides of the peninsula. A large region from Barletta to Gioia, on the Adriatic coast, also consists of it. Within the first-mentioned band, and resting upon this limestone, are scattered immense deposits of a coarse calcareous breccia, consisting of rounded masses of various sizes, (sometimes, as north of Potenza, very large, reaching eight or ten feet in diameter,) and cemented together, with similar but softer material, in ill-defined heavy beds, usually much less inclined, than those of the limestone beneath. Whether this rock belongs to the cretaceous series, or to what other, I am unable to say: it occupies the bottom of many of the narrow valleys, and in one place on Collegno's map, appears to be assigned to the pliocene tertiaries, but probably in error.
Above the lower limestone, reposing upon it, laid against its highy-inclined beds, and often mixed with it, in perplexing confusion—we find the nummulitic and hippurite limestones of the cretaceous formation, always characterized to the eye, even far away, by the want of clear bedding, the more rounded outlines, of the lower moun-
