iixtepetl itzalan.

Headword: 
iixtepetl itzalan.
Principal English Translation: 

a tree-covered mountain plain; a "flat surface between the mountains" (citing Sahagún)
Barbara J. Williams, "Pictorial Representation of Soils in the Valley of Mexico: Evidence from the Codex Vergara," Geoscience and Man 21 (1980), 51–62; see p. 57.

Attestations from sources in English: 

“Soils associated with mountain valleys or passes are suggested by a passage in Sahagún (1963, p. 262) that describes a tree-covered mountain plain as a ‘flat surface between the mountains,’ iixtepetl itzalan.” (p. 57)
Barbara J. Williams, "Pictorial Representation of Soils in the Valley of Mexico: Evidence from the Codex Vergara," Geoscience and Man 21 (1980), 51–62.