_Cayambe Urcu_, the summit of which is crossed by the equator, is noted as being the highest mountain of this range which has been yet measured, excepting only Chimborazo, as it is 19,386 feet above the level of the ocean. Its form is that of a truncated cone, and it is one of the most majestic and beautiful of those which surround the city of Quito. _El Corazon_, covered with perpetual snow, is so called from its summit having a heart-like shape. Bouguer ascended this mountain, and describes the frost as so great near the top, that his clothes, beard and eyebrows were covered with icicles; it is 15,795 feet above the level of the sea. _Ruminavi_ and _Ilinissa_, the latter of which is 17,238 feet above the level of the sea, and has its summit divided into two pyramidal peaks, join each other by a transverse chain, called the Alto de Tiopullo, Ilinissa being on the west, and Ruminavi on the eastern crest of the equatorial Andes. This chain bounds the valley of Quito on the south and separates it from the plains of Hambato and Latacunga; and the pyramids of Ilinissa are visible from the plain of Las Esmaraldas in Atacames. A most singular monument is observable on the top of the dyke or chain of Tiopullo, consisting of a tumulus, and the ruins of one of the Peruvian palaces called tambos, situated in a plain covered with pumice stones. The tumulus, if it be one, is upwards of two hundred feet high, and is supposed to have been the burying place of a chief. The palace is south-west of this hillock, nine miles from the crater of Cotopaxi, and thirty from Quito. It is in the form of a square, each side being about 100 feet in length, with four great doorways and eight chambers. Its walls are more than three feet thick, formed of large stones regularly cut and laid in courses, and the whole is in tolerable preservation. It is called the palace of Callo, but the great curiosity of this edifice consists in the beauty of the workmanship, as all the stones are cut into parallelopipedons, and laid in regular courses, and so nicely joined, that were it not that each stone is convexly and obliquely cut on the outside, their joints would not be visible. The volcano of _Sangai_, or _Mecas_, is the most southern mountain of Quito, and is covered with snow, but a continual fire issues from its summit attended by explosions, which are heard 120 miles distant, and when the wind is fair, are audible even at Quito. The country adjacent to this volcano is totally barren, being covered with cinders; in this desert the river Sangay rises, and joining the Upano, flows into the Maranon under the name of the Payra. Sangai is 17,131 feet above the level of the sea.