Structure of the Eastern Alps. 335 



a mere inspection of the accompanying section. We may further remark, 

 that notwithstanding the enormous disruptions of the strata on the banks of 

 the Iller, all the mountain-ridges preserve a very exact parallelism^ ranging- 

 through the Allgau in a direction about W.S.W. and E.N.E. These facts^ 

 as far as they go, confirm some of the remarkable speculations of M. Elie 

 de Beaumont, on the elevation of the principal chain of the Alps. Finally, 

 we may observe, that notwithstanding the constancy of the dip and the pa- 

 rallelism of the ridges, some portions of this section would probably give an 

 exaggerated notion of the thickness of the green-sand series. The great, 

 longitudinal breaks must unquestionably have been accompanied by vertical, 

 relative movements of the stratified groups ; in consequence of which some of 

 the groups may now be several times repeated on the same line of section. 

 The same observation may be applied to many other parts of the chain, and 

 will assist us, in some measure, in reducing our estimate of the total thickness 

 of the secondary series of the Alps. 



3. Transverse Section through the Alp-Spitz and Nesselwang, <^c. 



On skirting the Alps from Immenstadt to Nesselwang, a distance of about 

 fourteen miles, we saw many fine examples of derangements similar to those 

 above noticed ; and at the latter place we examined, in some detail, a trans- 

 verse section, which we now proceed to describe*. 



Immediately to the south of Nesselwang is a peaked range called Alp-Spitz, 

 the highest point of which rises about 1800 feet above the level of the town, 

 and consists of a bluish, thin-bedded limestone of shattery fracture, containing 

 Belemnites and many broken shells. These beds form a saddle at the summit ; 

 and in their range towards the south compose a succession of woody eleva- 

 tions, most remarkably contrasted with the bare precipices of older limestone, 

 which rise up beyond them. 



On the northern side of the Alp-Spitz, the strata decline from a nearly ver- 

 tical position, acquire a northern dip, and are overlaid by a thin-bedded, 

 grey limestone, containing large, turriculated shells, and many pyritous balls 

 (varying from the size of a pea to that of a walnut), which, in decomposing, 



Brora Coal-field. In that case, however, no trap rocks are visible ; but in the Isle of Arran the 

 secondary rocks are penetrated by trap, and are also elevated by the granite of Goatfell. The 

 granite was probably raised in mass by the same moving forces which propelled the trap. The 

 dislocation seems to have been precisely of a similar kind to that of the Bolghen. See Geol. 

 Trans. N. S. vol. ii. p. 293. and vol. iii. p. 34. 

 * Plate XXXVI. fig. 5. 



