252 COSMOS. 



divisions appeared to penetrate far into the interior. Fui ther 

 to the south of Lake Kolivan, towards the boundaries of the 

 Chinese province Hi (between Buchtarminsk and the river 

 Narym), the formation of the erupted rock in which there is 

 no gneiss, is more remarkable than I ever observed in any 

 other part of the earth. The granite, which is always covered 

 with scales and characterised by tabular divisions, rises in the 

 steppes, either in small hemispherical eminences, scarcely six or 

 eight feet in height, or like basalt in mounds, terminating on 

 either side of their bases in narrow streams.* At the cataracts 

 of the Orinoco, as well as in the district of the Fichtelge- 

 birge (Seissen), in Galicia, and between the Pacific and the 

 highlands of Mexico (on the Papagallo), I have seen granite 

 in large flattened spherical masses, which could be divided, 

 like basalt, into concentric layers. In the valley of Irtysch, 

 between Buchtarminsk and Ustkamenogorsk, granite covers 

 transition slate for a space of four miles,f penetrating into it 

 from above, in narrow, variously ramified, wedge-like veins. 

 I have only instanced these peculiarities, in order to designate 

 the individual character of one of the most generally diffused 

 erupted rocks. As granite is superposed on slate in Siberia, 

 and in the Departement de Finisterre (Isle de Mihau) so it 

 covers the Jura limestone in the mountains of Oisons (Fer- 

 monts), and syenite, and indirectly also chalk, in Saxony, 

 near Weinbohla. J Near Mursinsk, in the Uralian district, 

 granite is of a drusous character, and here the pores, like 

 the fissures and cavities of recent volcanic products, enclose 

 many kinds of magnificent crystals, especially beryls and 

 topazes. 



2. Quartzuae porphyry is often found in the relation ol 

 veins to other rocks. The base is generally a finely granu- 

 lar mixture of the same elements which occur in the larger 



* See the sketch of Biri-tau, which I took from the south side, where 

 the Kirghis tents stood, and which is given in Rose's Reise, bd. i. 

 s. 584. On spheres of granite scaling off concentrically, see my 

 Rclat. hist., t. ii. p. 497, and Essai Geogn. sur les Gisement des Roches, 

 p. 78. 



f Humboldt, Asic. centrale, t. i. pp. 299-311, and the drawings in 

 Rose's Reise, bd. i. s. 611, in which we see the curvature in the layers 

 of granite which Leop. von Buch has pointed out as characteristic. 



J This remarkable superposition was first described by Weisp, in 

 Rarsten's Archivfur Bergbau und Hiittenwesen. bd. xvi. 1827, s. j. 



