Because Miller connected “Monteray” with Guatemala and access to both the Atlantic and Pacific oceans, he appears to be referring to the capital of the Mexican state of Nuevo León (Monterrey), not the capital of the Mexican territory of Alta California (Monterey). One contemporary publication stated that Nuevo León “exhibits a good deal of fertility, but is little cultivated” and described how “large herds of cattle pasture on the plains” of that state. (Long, Geography of America and the West Indies, 177; see also [Folsom], Mexico in 1842, 98.)
Long, George, ed. The Geography of America and the West Indies. London: Society for the Diffusion of Useful Knowledge, 1841.
[Folsom, George]. Mexico in 1842: A Description of the Country, Its Natural and Political Features, with a Sketch of Its History, Brought Down to the Present Year. To Which Is Added, an Account of Texas and Yucatan; and of the Santa Fé Expedition. New York: Charles J. Folsom, 1842.