Structure of Granite, 5 



To this investigation likewise, and therefore to the attain- 

 ment of the object which has caused the present treatise, be- 

 longs the accurate knowledge of what has generally been 

 termed stratification (schichtung). Of the surfaces which 

 bound the cubic or cuboidal masses of granite, one, and gene- 

 rally that one whose position deviates least from horizontality, 

 is considered as what is termed a seam of stratification ( schich- 

 tung skluft)^ and the tabular masses contained between two of 

 such seams are considered as actual strata ; while the others, 

 which are nearly perpendicular to them, are regarded as mere 

 rents (zerspaltungen). The first of these conclusions is just 

 as inaccurate as the last ; for, when we compare with one an- 

 other the three different surfaces of separation which are dis- 

 tinguished by their position and direction, and when we com- 

 pare them with those which bound the indeterminately angular 

 pieces, we find that they correspond with one another per- 

 fectly in all essential properties or relations. But we cannot 

 regard any of the surfaces bounding the angular distinct con- 

 cretions as seams of stratification, as there are no strata pre- 

 sent which they could bound. And just as little can the one 

 or the other of the surfaces enclosing the cuboidal masses be a 

 seam of stratification, as they are not only nothing else than that 

 of which we have just spoken, but because they also all possess 

 equal claims to be considered a seam of stratification, while 

 only one of them can be so. Not one of them, therefore, is really 

 a seam of stratification. We certainly find that some varieties 

 of granite are somewhat more easily split in one direction 

 than in another. We might, therefore, be induced to regard 

 as seams of stratification those separating surfaces, which cor- 

 respond to this direction, and which are thus sometimes dis- 

 tinguished from the others. But this appearance is a mere 

 feature of the stony structure, and occurs only in those varie- 

 ties of granite in which the first commencement of a transition 

 into gneiss is noticeable in the somewhat lengthening form of 

 the portions of mica and felspai*. Where this does not take 

 place, the surfaces of separation, or the distinct-concretion- 

 surfaces, are all alike, and hence, not one of them can be re- 

 garded as a seam of stratification. This surface of separation, 



