- vations differ 9900 (10551 English) feet. In a similar
manner, in the Amuich Chain of the Caucasian Daghestan, the cretaceous beds rise from the banks of the Sulak, which are hardly 530 English feet above the sea, to a height of fully 9000 (9592 English) feet on the Tschunum; while on the summit of the Schadagh Mountain, 13090 (13950 English) feet high, the Ostrea diluviana (Goldf.) and the same cretaceous beds are again found. Abich's excellent observations in the Caucasus would thus appear to have confirmed in the most brilliant manner Leopold von Buch's geological views on the mountain development of the cretaceous group.
From the lonely grazing farm of Montan surrounded by herds of lamas, we ascended more to the south the eastern declivity of the Cordilleras, and arrived as night was closing in at an elevated plain where the argentiferous mountain of Gualgayoc, the principal site of the celebrated silver mines of Chota, afforded us a remarkable spectacle. The Cerro de Gualgayoc, separated by a deep-cleft ravine or valley (Quebrada) from the limestone mountain of Cormolatsche, is an isolated mass of siliceous rock traversed by a multitude of veins of silver which often meet or intersect, and terminated to the north and west by a deep and almost perpendicular precipice. The highest workings are 1445 (1540 English) feet above the floor of the gallery, the Socabon de Espinachi. The outline of the mountain is broken by numerous tower-like and pyramidal points; the summit bears indeed the name of "Las Puntas," and offers the most decided contrast to the "rounded outlines" which the miners are accustomed to attribute to metalliferous districts generally. "Our moun-
