54 Co Lal EIN CTE COCIE 
Valley in six or eight isolated areas, interspersed over a distance 
of a hundred and twenty-five miles, and covered by hornblende- 
schist occasionally. It has been located between the porphyritic 
and lake gneisses. The hornblende schist does not guide us 
satisfactorily to the upper formations; and hence other consid- 
erations must be taken into account in the further attempts at 
‘classification. Most of the remaining rocks are some form of 
‘mica schist. They are plainly above the gneisses, for wherever 
any of them come in contact with the feldspathic rocks they are 
superincumbent. They have been distinguished as the Montalban, 
or mica schists carrying some feldspar with fibrolite or andalusite; 
the group of hydromica schists; Rockingham mica schists; Mern- 
mack group and Ferruginous slates. After detailed studies our 
conclusion was that the Montalban preceded the hydromica schist 
‘which were closely related to the Kearsarge and Merrimack 
-schists and the Ferruginous slates of Hillsborough county. The 
-Rockingham schists simulated the Montalban. 
The hydro-mica schists are arranged primarily in two diver- 
gent lines, which are assumed to represent one grand formation, 
whatever its place in the scale may be. The best known is that 
\which starts in western Massachusetts under the old name of 
italcose schist, passes through central Vermont east of the Green 
-Mountains and continues past Quebec parallel to the St. Law- 
:rence River. Both the Vermont and Canada surveys recognized 
a similar (third) belt on the west side of the Green Mountains, 
extending as far south as Middlebury. The eastern line begins at 
Bellows Falls and is nearly continuous along the Connecticut to 
tthe mouth of the Passumpsic River, and thus expands to as 
great a width as that of the central belt, and it continues 
through the western edge of Maine into the Gaspé peninsula. 
iRanges of gneiss flank both these hydro-mica belts, viz., the 
«Green Mountain gneiss upon the west and the Connecticut band 
.of lake gneiss on the east, and with the same synclinal disposi- 
tion. Inside of the hydro-mica schists are belts of argillite, 
which seem to follow the same synclinal law of distribution. 
“There is left between the argillites an immense area which has 
