176 Prof. J. Noggerath on the Magnetic Polarity 



scientific one, as the journey had no scientific object, except 

 as to raining, and a general knowledge of the rocks forming 

 the surface. 



"Although an attempt may be made to form several of the 

 groups of basalt, with which the Eifel is scattered over, into 

 lines, there is none so long, and of which the range is so close, 

 as that round the Nurburg, one league and a quarter south of 

 Adenau. Its direction is meridional, with a slight inclination 

 towards the west. It begins in the S. near Bertrich (not far from 

 the Mosel), with the remarkable formation of basalt and scoria, 

 runs by Walmeroth, Ulmen, Horperath, over the high Kell- 

 berg, between the villages of Kellberg and Ursfeld, by the 

 Nurburg, the detached group near Adenau, with outliers as 

 far as the Hochthurn and Hasenberg, between Kirchsahr and 

 Altenahr. With the exception of the Hohen-Acht, two 

 leagues S.E. of Adenau, this line includes the highest masses, 

 exceeding all the summits of grauwacke-slate, on which they 

 stand ; such are the Hoh-Kellberg, the Nurburg, and the 

 Hochthurn. These cones rise between 1900 and 2000 

 Prussian feet above the level of the Rhine. There is no other 

 appearance of volcanic origin in the cones of this chain (ex- 

 cept at Bertrich and the Maars*) than in the basalts of the 

 Westerwald, Hesse, and Silesia ; and their nature would have 

 remained in doubt if the closely aggregated and undoubtedly 

 volcanic groups, running in a continuous range from the vol- 

 cano of Bertrich as far as Hillesheim, did not bear the clearest 

 evidence of it. I will not allude here to the volcanic range 

 accompanying the Rhine, as it would draw me too far from 

 my object, which is to show that the line of elevated basaltic 

 cones here described, seven German miles in length, in their 

 position nearly parallel with the magnetic meridian, may bear 

 a relation to the peculiar magnetic property of the rocks of 

 several of the hills of this line. I stood on the Michelstein, a 

 double-pointed hill of basalt ; on the northern mountain range 

 of the Eifel, the beautiful semi-circle of the high cones of 

 Hochthurn, Hohen-Acht, Nurburg, Kellberg, and Ahrem- 

 berg, lay before me. The Nurburg rose in apparently a spi- 

 ral form, which deception is increased by the ruined tower 

 standing on its summit. Three days after I ascended it, I 

 went up from Adenau as far as the Wimbacher-Hohe, be- 

 tween the village of Wimbach and Nurburg, where a promi- 



* The Maars are circular lakes among the grauwacke-slate, with steep 

 banks. Without any visible supply, they overflow copiously through an 

 aperture in their banks towards the neighbouring valley. Their highest 

 edge is covered partly with a stratum of volcanic grit, mixed with scoria 

 and pieces of slate, masses of augite and pieces of basalt, and partly with 

 an alluvial deposit of trappean substances. 



sing 



