6 . FRANK D. ADAMS 
actual contact with the intruding rock that the limestone was changed 
into an amphibolite. 
In addition to the amphibolites originating in the three ways above 
mentioned, it is highly probable, judging from their character and 
mode of occurrence, that the great amphibolite bands associated with 
large gabbro and diorite masses, as for instance that running in a 
northeasterly and southwesterly direction through the township of 
Wollaston, and that occurring in the southeast portion of the township: 
of Cardiff, thence crossing Chandos into Anstruther, represent chiefly 
highly altered basic volcanic ashes and lava flows connected with 
vents represented by the gabbro stocks. The latter of these amphib- 
olite bands presents a great variation from place to place in the 
character of the constituent rock. While in some places this amphib- 
olite is well banded, elsewhere it is streaked or presents an appear- 
ance strongly resembling flow structure, with lighter colored, lathlike: 
forms thickly scattered through it which are highly suggestive of 
feldspar phenocrysts, while elsewhere again it presents an appearance 
suggestive of an original amygdaloidal structure. The rock, however, 
is so completely recrystallized that a microscopic examination does not 
yield any conclusive evidence concerning its original character. 
That amphibolites do originate in the first manner described is 
clearly seen and easily understood, and that they originate in the 
second manner referred to is well known and has been described in 
many localities, but that they may originate also in the third way above 
mentioned is not so generally recognized, and this mode of origin. 
therefore merits a further consideration. 
DEVELOPMENT OF AMPHIBOLITE AS ONE OF THE CONTACT PHENOMENA. 
ABOUT THE BORDERS OF THE GRANITE BATHYLITHS 
About the borders of the various areas of granite, contact action 
is pronounced and often very striking. If the invaded rock be 
amphibolite, fragments torn from it are found scattered about in the: 
gneiss, in the form of inclusions. 
When the granite invades bodies of limestone, on the other hand, 
the phenomena resulting from the intrusion are more varied. ‘The 
invading rock metamorphoses the limestone and the products of altera-- 
tion may be divided into three classes: 
