The Schists. 
218 
of the later force coincided with the greatest stress of the ear¬ 
lier force. Where maximum forces combine, there would occur 
the greatest dynamic disturbance. These centres of foci would 
occur only at intervals, the intervening areas being compara¬ 
tively undisturbed. Regions of very marked disturbance occur in 
Conanicut: these regions are widely scattered and do not occur 
in any definite order, the most noticeable points are Freebody’s 
Hill, Beaver Head and Lion’s Head. The surfaces of the rocks 
in these areas show slickensided surfaces, caused by the sliding 
of blocks along the planes of schistosity, c the smooth sericite 
schists especially affording easy movement along such surfaces. 
There has been comparatively little true faulting, most of the 
movements have been along the gliding planes caused by schis¬ 
tosity. In addition to the slickenslides another interesting 
feature is noticeable. The schistose planes are often wrinkled 
by minute folds, rarely over 2 or 3 inches across and usually 
much smaller, the strike of these folds is quite uniform in the 
same locality and is approximately N. E. to S. W. 
The schistose planes are frequently much contorted and dis¬ 
turbed on a small scale by the dynamic force which produced 
this folding. This force must have acted after the principal 
schistosity of the rocks was developed, in many cases this force 
was sufficiently powerful to develop schistosity of its own. 
Where this is the case, there occurs the double schistosity al¬ 
ready mentioned. The schists in their present condition indi¬ 
cate at least three orographic movements: First, the move¬ 
ment which produced the principal folds of the island and 
tilted the rocks into their present position. This movement 
acted approximately in an easterly direction, the strike of 
the folds and of the rocks in the aggregate is nearly north 
and south. In many cases the schistosity, which has been 
developed to so remarkable a degree in these rocks coin¬ 
cides with the dip of the bedding, it may be presumed that 
this schistosity was developed pari passu with the tilting of 
the rocks, and that both processes were due to dynamic press¬ 
ure. In many instances, however, there is discordance be¬ 
tween the two. The banded schists already mentioned stand 
vertically while the schistosity is horizontal, the schistosity 
