66 



tallization brought about by metamorphic processes. It 

 presents no evidence of crushing or of having been caused 

 to move since its recrystallization took place. This 

 structure is quite distinct and different from that seen in 

 the little injected bands of granite. In these, which are 

 composed of quartz, microcline, orthoclase and plagioclase, 

 the quartz occurs for the most part in thin leaves with 

 undulatory extinction and the structure of the rock is 

 suggestive of the "mortel" or granulated structure seen 

 in the granite gneisses. 



In this remarkable occurrence, therefore, the crystal- 

 line limestone can be seen under the influence of the granite 

 intrusion to have changed into a typical hornblende-feld 

 spar amphibolite, having passed through the intervening 

 stage of a pyroxene-scapolite-hornblende-feldspar amphib- 

 olite (pyroxene-scapolite gneiss). 



Three specimens of these amphibolitic rocks from 

 Maxwell's Crossing, chosen to represent three steps in the 

 progressive change from limestone to amphibolite, have 

 been analysed by M. F. Connor, of the Department of 

 Mines. The figures given are in every case the mean of 

 two determinations which agree closely with one another. 

 The results of these analyses are as follows: — 



No. 1. 



(a) 



(b) 



No. 2. 



No. 3. 



Si0 2 .. 

 Ti0 2 .. 

 A1 2 3 . 

 Fe 2 3 . 

 FeO.. 

 MnO. 

 CaO.. 

 MgO. 

 K 2 0.. 

 Na 2 0. 

 C0 2 .. 

 CI.... 

 S.... 

 H 2 0.. 



32-88 

 0-49 

 9-04 

 o-77 



3-48 



30-90 



4-18 



0-85 



1-17 



15-20 



undet. 



undet. 



1-08 



100-04 



50-20 



o-75 



13-80 



i-i8 



5-3i 



17-71 

 6-38 

 1-30 

 1-79 



i-66 

 100-08 



99-97 



99-48 



