266 Sir Alexander Crichton on some Par^s ©/"^Ae TflMnws; ' 



western one. The extent from south to north along the Rhine is from Ass- 

 manshausen, nearly opposite to Mayence, to a little below the mouth of the 

 river Lahn, in the neighbourhood of Coblentz. The group of mountains called 

 the Hundsruche on the west of the Rhine, is in point of fact a continuation 

 of this chain, being- of the same geological character and lying in the same 

 direction. The mountains of Nassau are divided by the valley of the Mayne 

 from the mountains of the Spessart and the Odenwald on the south. After 

 being interrupted by the basalt of the Westerwald on the north, they sink 

 under the formations of Westphalia. Any one travelling from Mayence to 

 Francfort sees on his left hand the whole chain of what ought strictly to be 

 called the Taunus Mountains. Their highest point is the Feldberg, esteemed 

 to be about 2600 Parisian feet above the level of the Mayne. 



This chain, which is the highest in the dutchy, differs from the minor 

 groups which lie to the north of it, inasmuch as it is composed of talc slate and 

 quartz slate on its south side, and of grauwacke on the north declivity. The 

 talc slate dips downwards, running into the mountains with a north-west 

 direction, while the grauwacke on the opposite side rises upwards from the 

 valley in a south-east one. The south brow of the mountain is made up of 

 the basset ends of the talc slate. Its direction and inclination may be traced, 

 especially close to Wiesbaden, in numerous and extensive quarries. The in- 

 clination and direction of the grauwacke, on the opposite side, are exposed to 

 view by natural sections, wherever the ground is bare. 



This kind of structure leaves on the summit a space or trough, to be filled 

 up, either with very short strata, or with some unconformable matter. The 

 summit is everywhere composed of a thick bed of quartz-rock. 



Altiiough this quartz is very compact and tough in many places, yet with a 

 good glass, scales of talc may be discovered in it. In some parts it is dark- 

 coloured, also red, and ferruginous; in others, white or gray. Two places were 

 pointed out to me, (by Mr. Stifft, general superintendant of the mines of Nas- 

 sau, to whose kindness and accurate knowledge of the dutchy I owe much of 

 what 1 saw,) in which the quartz formed isolated rocks about 16 feet high on 

 the summit of the ridge. They lie on the right of the road from Wiesbaden 

 to Ems, in the middle of a forest, and are known by the names of the Spitzer- 

 stein and Alterstein. 



The mixture of iron oxyd and talc, by permitting the admission of mois- 

 ture, favours disintegration; and as the brow of the mountain is covered with 

 blocks and fragments of it, there is good reason for supposing that the Spit- 

 zerstein and Alterstein are the remains of a higher ridge. 



