64 On the Basaltes of Saxony. 



5th, The Lichtewalde is the object of more important 

 considerations. The body of this mountain is composed of 

 large-grained reddish granite* It is terminated by a mass 

 of basaltes not less perhaps than 200 yards in thickness, 

 and about 1000 in diameter. It is not easy to determine 

 whether it be divided into prisms. It is of a grayish, black 

 colour ; some blocks of it are entirely pierced with tortuous 

 cavities. These are lighter, and have less hardness than 

 common basaltes. But what in particular distinguishes the 

 basaltes of this mountain is the quantity of beautiful olivin 

 which it contains. It appears in irregular morsels some* 

 times larger than the fist. 



6th, The Steinkopf, an oblong mountain the base of which 

 is of gneiss, and the upper part of porphyry, a pate argil- 

 lease rouge. On the back of the porphyritic part is found a 

 basaltic summit divided into prisms, which contains a ca^ 

 vity two or three yards in depth and about four in diameter, 

 the sides of which are composed of prisms, that proceed di- 

 verging like the radii of a hemisphere the centre of which 

 is in the middle of the depression. The basaltes here is very 

 hard, and of a dark colour. It contains a little olivin, and 

 grains of magnetic iron ore. t . 



7th, The Landbcrg is gneiss, covered on the side with 

 argillaceous schist and porphyry, having a base of compact 

 feldspar : over this porphyry is extended a stratum of gres 

 which supports the basaltes. The latter is divided into 

 plates ; but this division ought not to be considered as the 

 work of stratification. On the eastern declivity of the 

 mountain is a s-mall cavity three yards in depth and two 

 and a half in breadth. This has been considered as the 

 crater of a volcano. This hole exhibits only fragments of 

 basaltes, and an earth somewhat rough to the touch, which 

 results from the imperfect decomposition of some parts of 

 the same rock. 



8th, Ascher-higel is a small eminence of grcs, the ridge 

 of which is formed by a thin stratum of basaltes divided 

 into irregular vertical prisms. In some of this basaltes the 

 author found fragments of gres. 



9th, Geissingenberg is a large mountain where tin ore, 

 disseminated throughout a quart zy substance impregnated 

 with chlorite, is worked in the mines known by the name 

 of Altenberg. Above this substance, towards the west, is a 

 kaW mass of porphyry with a base of hornstein ; but to- 

 wards the east it is gneiss covered by sienite of a porphyritic 

 structure. On the'back of the .mountain rests a basaltic 

 excrescence the circumference of which is nearly a thousand 



yards 



