

128 HOLLAND: GEOLOGY OF THE NEIGHBOURHOOD OF SALEM. 



The appearance of the needles in the garnets seems to be always 

 accompanied by schillerization of the associated 



Coincident schilleriza- ,,. . Pjl , - ... 



tion of the other constituents of the rock, and on this account 



it has been suggested that the schiller inclusions 

 in the pyroxenes, amphiboles and felspar are due to a cause 

 similar to that which produced the needles in the garnet and, in the 

 acid members of this series, the needles found in the quartz {supra, 

 page 17). 



It is very interesting to observe that all the old rocks in the 

 neighbourhood of the Chalk hills, including the Shevaroys, are 

 well schillerized. It is just possible that the great peridotite 

 intrusions of the Chalk hills may have been connected with the 

 circumstances which favoured this schillerization of the rocks 

 around; and in this connection it is worthy of note, though it 

 may be a mere accidental coincidence, that the garnets, in which 

 Diller found needles similar to those herein referred to, were found 

 near a peridotite intrusion. 



Ultra- basic forms* 



It is quite common, especially in the immediate neighbourhood 



PyroxenitesandAmphi- of the basic ga™etiferous varieties, to find 

 bole rocks. lenses, bands and small dyke-like formations 



practically devoid of felspar. In the majority of these pyroxene 

 predominates, whilst in others the hornblende is in excess of the 

 pyroxene. Trains of lenses of the former kind, pyroxenite, occur 

 along the northern foot of the hill west-south-west of Salem 

 ( 1 1*900). The lenses are very variable in size, but are often a foot 

 or two wide and some four to six feet long. Although these lenses 

 are distributed along the foot of the hill parallel to the foliation of 

 the basement rocks, they do not occur strictly confined to one band, 

 but are arranged en echelon ; this indicates that they have not been 



( 26 > 



