Bibliographical Notice. 409 
than the plateau, though in distance but a few miles off. Three or 
four thousand miles of latitude would not give a greater difference.” 
The great barranca of Regla is next described (p. 89). The 
oaks at the top of the barranca, with their branches fringed with the 
long, grey “Spanish moss” and a profusion of brightly blossoming 
epiphytes clinging to their bark, claimed attention, as well as the cac- 
tuses, of many species. The great valley itself—a mile or two in width, 
with sides almost perpendicular, and capped with basaltic pillars, and 
atthe bottom a strip of lend where the vegetation is of the deepest 
green of the tropics, with a river winding along among palm-trees and 
bananas—is between two and three thousand feet deep ; and the view 
is wonderful. 
The author makes the following among other notices of the mining 
establishment at Real :—‘ The original English company spent nearly 
one million sterling on it, without getting any dividend. They sold 
it to two or three Mexicans for about twenty-seven thousand pounds ; 
and the Mexicans spent eighty thousand more on it, and then began 
to make profits. The annual profit is now some £200,000” 
(p. 107). 
The Dae cascade of Regla, near the silver-mines, is illustrated 
by a lithograph (frontispiece), copied from a good photograph, and 
is described, with its precipitous walls of columnar basalt and gigan- 
tic yuecas. Joints of these columns are used as crushers in the ore- 
crushing mill, being dragged round and round, by mule-power, on a 
floor made also of basalt. 
Near Regla occur the quarries of obsidian, at the Cerro de Nava- 
jas (“‘ Hill of Knives”), where the Aztecs worked that stone into 
knives and other implements in immense quantities. At Teotihuacan, 
also, was a similar knife-manufactory. Valuable information on this 
subject is given at pages 96, 137, &c., and in the Appendix. Not 
far from this are the Pefas Cargadas (‘‘ the Loaded Rocks ”’)— 
‘several sugar-loaf peaks, some three hundred feet high, tapering - 
almost to a point at the top, and each one crowned with a mass of 
rocks, which seem to have been balanced in unstable equilibrium on 
its point, looking as though the first puff of wind would bring them 
down. The pillars were of porphyritic conglomerate, which had been 
disintegrated and worn away by wind and rain ; while the great masses 
resting on them, probably of solid porphyry, had been less affected 
by these influences”’ (pp. 94 and 95). 
Among other geological phenomena, the accumulation of alluvium 
at Tezcuco is described ; and the value of the evidence that alluvial 
deposits bear respecting chronology in Mexico, Egypt, and Sicily is 
briefly discussed. ' 
The great stalactitic cave of Cacahuamilpan, vast and beautiful 
(pp. 203, &c.), and the great cone and crater of Popocatepetl (pp. 
236, &c.) were visited, and are carefully described ; and amongst the 
more or less common objects of natural history, the aloes (and the 
making of pulque), ants, cactuses, cypress-trees, edible insect-eges of 
the Tezcuco Lake, hill of magnetic iron-ore of Huetamo, saline condi- 
tion of the soil, and sand-pillars are described in some detail, and may 
