214 HOLLAND: CHARNOCKITE SERIES. 



through the end of one of the lenses, giving a very clear section of 

 the tapering edge of the lens in the highly crushed schists. 



As a general rule the rocks immediately bordering these lenses 

 are highly crushed, often crushed beyond all 



Lenticular habit. . . . . . 



possible recognition of individual minerals, 

 whilst those which form the lenses may show merely a directional 

 disposition of constituents parallel to the long axis of the lens, but 

 otherwise show no signs of having been subjected to exceptional 

 pressure ; sometimes, indeed, they are quite massive. Two alter- 

 native explanations naturally suggest themselves by these 

 phenomena: either the lenses are bands pinched out by pressure, 

 or they are the result of intrusion between the already foliated 

 schists. In some cases it can be shown quite distinctly that the 

 lenses are not arranged along the same band of the schists ; that in 

 fact, they are disposed en echelon with their long axes parallel to one 

 another though not in the same line. Such instances are seen to the 

 north of Karipatti, and indicate that the first explanation is probably 

 not applicable to all cases. The second explanation, namely, lenticu- 

 lar intrusions between the schists, is more generally satisfactory. 

 Reyer would probably regard these lenticular masses as Kuppen, as 

 he does in the case of the roughly lenticular granulite complex of 

 Saxony. 1 



But whether these rocks occur as small lenses, or whether 

 they form the larger boss-like masses, the one 



Homogeneity. . . . . ■ " - 



important point is the uniformity or average 

 composition and character throughout, an uniformity of the kind 

 with which we are familiar in large bosses of igneous rocks, but 

 of which we have no parallel amongst those of sedimentary 

 origin. Amongst sedimentary rocks our most uniform types are the 

 marine limestones which are formed in the deep sea, where consider- 

 able changes of level are required to bring about noticeable variety 

 in the lithological characters of the products. Under the condi- 

 tions prevailing within short distances of the coastal region small 



1 Theoretische Geologie, 1888, p. 533. 



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