The pyramid marked A in the plan is known as Metztli Itzacual, which is interpreted “House of the Moon.” It measures 156 metres or 512 feet from east to west by 130 metres or 426 feet from north to south. According to Almarez, its height is 42 metres or 137 feet, but Sr. Garcia y Cubas, who took his measurement on the opposite side of the pyramid from that measured by Almaraz, says that it is 46 metres or 150 feet high. The summit platform, according to Garcia y Cubas, is six metres or nineteen and a half feet square; quite a discrepancy is here observable between the estimated area given by Beaufoy and copied by Mr. Bancroft as thirty-six by sixty feet, and this actual measurement. The sides of the pyramid nearly face the cardinal points. The eastern slope is 31° 30′, while the southern is somewhat steeper, being 36°. The slope on the east seems to have been unbroken except by a zigzag roadway, leading to the summit. The remaining sides are plainly marked by the remains of three terraces, one of which is still about three feet wide. Humboldt and Tylor both speak of remains of stairways of which no mention is made by the Government Commission. Most observers have described the pyramids as faced with hewn stone, but the commissioners on the contrary found them coated with successive layers of different conglomerates as follows: “1st, small stones from eight to twelve inches in diameter, with mud forming a layer of about thirty-two inches; 2d, fragments of volcanic tufa, as large as a man’s fist, also in mud, to the thickness of sixteen inches; 3d, small grains of tetzontli (a porous volcanic rock) of the size of peas, with mud, twenty-eight inches thick; 4th, a very thin and smooth coat of pure lime mortar. These layers are repeated in the same order nine times and are parallel to the slopes of the pyramid, which would make the thickness of the superficial facing about sixty feet.”[546] On the southern slope, sixty-nine feet from the base, according to Almarez, a gallery large enough to admit a man crawling on hands and knees, extends inward on an incline, a distance of twenty-five feet, and terminates in two square wells or chambers, each five feet square, and one of them fifteen feet deep. Mr. Löwenstern, according to Mr. Bancroft, states that “the gallery is a hundred and fifty-seven feet long, increasing in height to over six feet and a half, as it penetrates the pyramid; that the well is over six feet square, extending apparently down to the base and up to the summit; and that other cross galleries are blocked up by débris!” It is probable that these remarkable galleries never existed, except in Mr. Löwenstern’s imagination, since Sr. Almarez in the report of the official survey pronounces the tunnel already described as simply excavations by treasure-hunters. The pyramid B of the plan, situated five hundred and seventy-five yards south of the House of the Moon, is called Tonatiuh Itzacual, or “House of the Sun.” This pyramid requires