p. 297

307 Aztalan

This ancient artificial earthwork consists of an oblong enclosure about five hundred and fifty yards in length and two hundred and seventy five yards in breadth, lying along the bank of the river. The walls are twenty three feet wide at the base and four or five feet high, having (except on the river side) an exterior semi=circular enlargement or buttress, and corresponding interior recess every twenty seven yards. In some parts of the wall and especially in the buttress, the earth of which it is composed, appears to have been mixed with straw and burnt in such manner as to resemble slightly burnt brick. There is no evidence that this substance was ever moulded into regular form. Within this enclosure are several remarkable mounds and excavations, and an unusual number of mounds (many of them very large) are found in the immediate vicinity, indicating that this spot was once occupied by a very numerous population, which continued

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