ANNOTATIONS AND ADDITIONS. 331 



different families of the present vegetable world, remind us that 

 many intermediate links have perished. Coniferse abounded in the 

 Ancient World : their remains, belonging to an early epoch, are found 

 especially in association with Palms and Cycadeae; but in the latest 

 beds of lignite we also find pines and firs associated as now with 

 Cupuliferse, maples, and poplars. (Cosmos, bd. i. s. 295298, and 

 468-470; Engl. edit, pp. 271-274, and Ixxxix.) 



If the earth's surface did not rise to considerable elevations within 

 the tropics, 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 determina- 

 tion of the exact lower and upper limits of the region of Coniferse 

 and of oaks in the Mexican highlands. The heights at which both 

 begin to grow (los Finales y Encinales, Pineta et Quereeta) 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 Mex- 

 ico, a little below the Venta 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 be- 

 gin to be found near a hut called Venta de la Moxonera, 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 Pa- 

 cific side, in the Alto de los Caxones north of Quaxiniquilapa, we 

 found this limit for Pinus Montezumse (Lamb.), which we at first 

 took for Pinus occidentals (Swartz), at an elevation of 3480 (3709 

 E.) feet; while towards Vera Cruz, on the Cuesta del Soldado, pines 

 are first met with at a height of 5610 (5980 E.) feet. Therefore 

 both the kinds of trees spoken of above, oaks and pines, descend 

 lower on the side of the Pacific than they do on the side of the An- 

 tillean 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 Mon- 

 tezumse at 12,138 (12,936 E.) feet above the sea, or almost 2000 



