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Show ANNOTATIONS AND ADDITIONS. 331 different families of the present vegetable world, remind us that many intermediate links have perished. Coniferre abounded in the Ancient World: their remains, belonging to an early epoch, are found especially in association with Palms and Cycadere; but in the latest beds of lignite we also find pines and firs associated as now with Cupuliferre, maples, and poplars. (Cosmos, bd. i. s. 295-298, and 468-470; Engl. edit. pp. 271-274, and lxxxix.) H the earth's surface did not rise to considerable elevations within the tropic , the highly characteristic form of needle-leaved trees would be almost unknown to the inhabitants of the equatorial zone. In common with Bonpland, I have labored much in the determination of the exact lower and upper limits of the region of Coniferre and of oaks in the Mexican highlands. The heights at which both begin to grow (los Finales y Encinales, Pineta et Querceta) are hailed with joy by those who come from the sea-coast, as indicating a climate where, so far as experience has hitherto shown, the deadly malady of the black vomit (Vomito prieto, a form of yellow fever) does not reach. The lower limit of oaks, and more particularly of the Quercus xalapensis (one of the 22 Mexican species of oak first described by us), is on the road from Vera Cruz to the city of Mexico, a little below the V enta del Encero, 2860 (3048 E.) feet above the sea. On the western side of the highlands between the city of Mexico and the Pacific, the limit is rather lower down, for oaks begin to be found near a hut called V enta de la Moxon era, between Acapulco and Chilpanzingo, at an absolute elevation of 2328 (2480 E.) feet. I found a similar difference in the height of the lower limit of pine woods on the two sides of the Continent. On the Pacific side, in the Alto de los Caxones north of Quaxiniquilapa, we found this limit for Pinus Montezumre (Lamb.), which we at first took for Pinus occidentalis (Swartz), at an elevation of 3480 (3709 E.) feet; while towards Vera Cruz, on the Cuesta del Sol dado, pines are first met with at a height of 5610 (5980 E.) feet. Therefore both the kind of trees spoken of above, oaks and pines, descend lower on the side of the Pacific than they do on the side of the Antillean sea. In ascending the Cofre di Perote, I found the upper limit of the oaks 9715 (10,354 E.) feet, and that of the Pinus Montezumre at 12,138 (12,936 E.) feet above the sea, or almost 2000 |