206 REPORT ON CORRELATION 
where the committee formerly examined it. ‘To the north of Halibur- 
ton it is flanked by another bathylithic mass similar to that just des- 
cribed. 
In this connection it should be remarked that, while the sedi- 
mentary rocks of this district have been referred to as the limestone 
series, this name has been adopted because in this series limestone 
is the dominant rock. ‘The limestone is, however, commonly impure, 
not infrequently passing into phases in which the non-calcareous sedi- 
ments are important or even dominant. Locally the sediments 
were apparently of the nature of altered volcanic fragmental material. 
This heterogeneity of original composition naturally leads to very 
great variety in the metamorphosed products, which vary from gneiss 
through calcareous schists to marbles and several varieties of 
amphibolites. 
At Haliburton the field-work of the committee was brought to a 
close. 
III]. RESUME OF THE GEOLOGY OF THE ADIRONDACK AREA 
So far as known, the oldest series of rocks in the Adirondack 
area consists of strongly and coarsely crystalline limestones, ophical- 
cites, quartzites, quartz-schists, rusty, micaceous, thinly foliated 
gneisses and more massive gneisses. Among these the limestones 
are on the whole the ones most easily recognized. On the east they 
are well and prominently developed. In the central area they seem 
to be extensive, but are poorly exposed, and quartz schists are promi- 
nent. On the northwest they appear in largest amount and form 
continuous belts over long distances. ‘The limestones are usually 
charged with bunches and streaks of silicates, which are in part torn 
and sheared intrusives, in part pegmatites, and probably also in part 
former siliceous, ferruginous, aluminous bands. 
The quartzites on the east are best developed near South Bay, 
one of the two southern arms of Lake Champlain. They are thor- 
oughly recrystallized, and all original clastic structure has been de- 
stroyed. They may contain great proportions of feldspar, and may 
also have sufficiently large percentages of graphite to be mined for 
this mineral. These feldspathic varieties were doubtless originally 
shales. 
