The lacustrine deposits in the department of the Haute Loire are nearly identical with those now described, but concealed very much by the lava and scoriæ that have flowed out in immense quantities in the trough of the river. The best sections are exposed near the town of Le Puy, where the sedimentary and erupted rocks are beautifully interstratified. The Aurillac basin, in Cantal, is filled with similar materials, although there is a greater proportion of silicious strata mixed with the calcareous marls. Indeed, so much in this district does the silex predominate, that a bed of tertiary limestone is covered with nodules of flint, and resembling in appearance the upper chalks of England. The fossil remains, however, clearly mark the distinction, where we have the shells of the _Planorbis_ for those of the _Echinus_, and other fresh water testacea instead of the marine types of the Cretaceous formation. IV. GENERAL CONCLUSIONS. This district has been the theater of great volcanic action. The epoch of its activity is clearly determined by the undoubted tertiary character of the formations with which its porous lavas and scoriæ are intermixed. Basalts and trachytes, of the same age, texture, and qualities, are to be found in the various countries through which the deposits have been traced. The granites, porphyries, and greenstones we have seen successively employed in raising up the symmetrical rocks of the grand palæozoic systems, and thereby giving shape, stability, and access to the economic and gradually-augmenting volume of the crust of the globe. Can we see in these last extinct throes of the interior, the operations of the same great FINAL CAUSE—the overruling hand of power, wisdom, and goodness in the mineral arrangements and diversified ingredients of our earthly habitation?