48 M. Mobs' Summary of Geognostical Phenomena. 



of all in the tract under consideration. We must, at the same 

 time, just as in the case of primitive and transition-rocks, by 

 no means assume the universal, regular, bed-like form, although 

 it occurs more frequently here than in these rocks ; and we 

 must not regard tabular division as actual stratification, al- 

 though it is the so-termed secondaiy rocks in which actual 

 stratification presents itself, with all its characteristic features. 

 It is well known regarding gypsum, that it frequently occurs 

 in amorphous irregular masses, but limestone and sandstone, 

 likewise, are met with in that manner ; and we must therefore 

 attend particularly to this point, because the contractions or 

 compressions, standing in connection with such widenings or 

 enlargements of size, often go to such an extent, that the one 

 or the other rocky mass disappears, at least for certain distances, 

 and does not make its appearance where it would be expected, 

 in the natural order of succession of strata. It is self-evident 

 how important this feature is, in the preparation of sections of 

 such a district. 



On the Bendings and Contortions of Strata. — Another sub- 

 ject worthy of attention is that of the frequent bendings and 

 contortions, partly of the real strata, partly of the mere con- 

 cretionary portions, from which arise saddles, troughs, and 

 some other similar phenomena, and the position more or 

 less approaching to the perpendicular of the already men- 

 tioned tabular divisions, with which it has even been at- 

 tempted to place in connection, by means of elevations and 

 tiltings, the invertion of the usual oi'der of certain moun- 

 tain-masses. If it be desired to know in reality the nature 

 of such phenomena, it is necessary for the observer to be 

 without prejudice, and without bias to a particular theory, 

 still not superficial, or inclined to suppose that he sees through 

 the thing at the first glance, but, on the contrary, it is neces- 

 sary for him to investigate the matter from the foundation, 

 and without regard for the expenditure of a certain amount 

 of time ; for, when one single such relation is quite thoroughly 

 understood (which is not so frequently the case as is believ- 

 ed), it may not only be the cause of an important saving of 

 time, but also the source of important discoveries. Should 

 such phenomena depend merely on distinct concretions, we have 



