humboldt's "cosmos." 405 



usually covered with innumerable detached blocks, probably owing to the con- 

 traction and cracking of an outer shell of granite while cooling. * In Northern 

 Asia again, in the beautiful and romantic neighbourhood of the Kolivan Lake 

 on the north-western flank of the Altai mountains, and also on the slope of the 

 coast chain of Caracas, near las Trincheras, I have seen the granite in step- 

 like terraces ; this peculiar form being probably due to a similar contraction 

 which has taken place deep in the recesses of the earth. Further towards the 

 south, advancing from Lake Kolivan towards the limits of the Chinese province 

 of Hi, the appearance of the igneous rocks, here quite unaccompanied by gneiss, 

 is more striking than I have seen in any other part of the world. The granite, 

 always comparatively flat and characterised by its tabular form, appears in the 

 steppes, sometimes in small hemispherical hillocks from six to eight feet high, 

 sometimes in projecting erupted masses, like walls of basalt appearing above the 

 surface. At the cataracts of the Orinoco, as in the Fichtelgebirge and in Galicia, 

 and between the southern lake and the high table land of Mexico (at Papagallo), 

 I have seen granite in great flattened spherical masses, exhibiting, when broken, 

 a concentric structure like basalt ; and in the Irtysh valley (in Siberia) the 

 granite for some miles overlies clayslates of an ancient date, and penetrates 

 them in numerous small wedge-shaped veins from above. I have only quoted 

 these isolated examples to show how universally the eruptive character is ex- 

 hibited in a rock so widely distributed ; and we find that just as in Siberia, in 

 the instance last quoted, and in the department of Finisterre (Isle de Mihau) the 

 granite rests upon slate, so in the mountains of Oisons( Fermonts), it covers the 

 rocks of the Jura formation, and at Weinbbhla, in Saxony, the cretaceous rocks 

 which again themselves repose on syenite. In the Ural also (near Mursinsk), 

 the granite contains cavities, and, as is the case with cavities and crevices in 

 modern volcanic rocks, so here they are occupied by beautiful and perfect 

 crystals, especially of beryl and topaz. — p. 261. 



Having briefly alluded to the ordinary phenomena of the earth's 

 structure, the metamorphic (next to the igneous rocks) supplying 

 our author with the chief subjects for discussion, he proceeds to the 

 consideration of the important problem as to whence were derived 

 the materials of, and where were deposited the most ancient sedi- 

 mentary rocks of our globe (p. 299.), and what form was assumed 

 when dry land first appeared above the waters. " The result of 

 investigations regarding the superficial relations of dry land is, 

 that in the earliest, viz. in the Palaeozoic periods as well as in the 

 most ancient secondary periods, the uncovered surface which was 

 clothed by land plants was limited to detached islands ; that after- 

 wards these islands were united with one another, and included 

 many lakes along the deeply penetrating bays of the sea; and 

 lastly, that when the mountain chains of the Pyrenees, the 

 Apennines, and the Carpathians were elevated, therefore at the 

 period of the older tertiary strata, vast continents, having nearly 

 their present size, made their appearance. In the Silurian world, 

 as well as during the period characterised by a profusion of 

 Cycadece, and by gigantic Saurians, the amount of dry land from 

 pole to pole was probably less than it is at present in the South 

 Sea and the Indian Sea." (p. 302.) The consideration of this sub- 

 ject leads to a disquisition concerning the effect of the actual dis- 

 tribution of land and water on climate, and the general physical 

 results of the actual configuration of the earth's surface at present; 



* See von Buch's paper on this subject, translated in the first Number of this 

 Journal, ante, p. 126. 



