Still we should remark that in Mexico the expressions "heat," and "cold," have not an absolute value as in Europe, and that the lofty plateaux, known as the tierras frias, enjoy a temperature like that of Lombardy, which would seem to any European a very pleasant climate. Owing to its position, Guadalajara shares in two of the three zones that divide Mexico. Situated on the limit of the tierra caliente and the tierra templada, the tepid breezes and pure sky reveal the warm regions of the seaboard, which extend thus far. The arid sands are succeeded by fertile and well-cultivated plains, fields of sugar-cane, Indian corn, bananas, goyaviers, and other productions of the tropical flora. By degrees the gloomy black oaks and pines, which only grow on the mountains, become rarer, and eventually disappear entirely, to make room for poplars, fan-palms, calabash trees, sumachs, Peru trees, and thousands of others, which proudly wave their superb crowns over the spontaneous vegetation that surrounds them.