214 
Collie—Geology of Conanicut Island , R. I. 
often dips N. E. or S. W., while the bedding dips E. or W., in 
such cases it is probable that the schists were tilted before 
schistosity was developed, and that later movements have caused 
this discordant schistosity. At least it is necessary to suppose 
that tilting had gone on for some time before the dynamic press¬ 
ure was sufficient to develop schistose planes and hence there 
Is no agreement between the bedding and the schistosity. This 
seems to be the most probable explanation of the relation of 
bedding and schistosity in the banded schists, the rocks had 
reached a vertical position before schistosity began to be de¬ 
veloped. These schists were in the center of folds, where they 
were closely appressed and where the folding process would be 
resisted by the weight of the superincumbent rocks thus pro¬ 
ducing vertical pressure, which would produce horizontal 
schistosity. Frequent but small faults occur in the banded 
schists indicating that pressure was also relieved by faulting, 
as well as by the production of schistosity. Second, the changes 
in the direction of the dips of the schistose planes from their 
normal E. or W. dip seems to be caused by a second force 
which bent or warped the schistose planes. The dip grad¬ 
ually changes from E. to N. E. and vice versa, or from W. 
to S. W., it is an appressing of the schistose planes on a large 
scale, causing them to frequently change their direction of dip. 
Third, as already indicated the schistosity is folded and puck¬ 
ered on a minute scale by a third but relatively feeble force, 
which judging from the direction of the minute folds, acted from 
the N. W. 
Thus far the schists have been described up to Round Swamp 
and Freebody’s Hill. A line connecting these two points sepa¬ 
rates in bulk the black and white schists. North of this line 
they are predominatingly dark colored. The dip and strike 
agrees with that of the more southern schists. The schistosity 
is not as perfect as in the light schist. The rocks are softer 
and more unctuous to the feel, and when wet are easily crumbled 
and form a saponaceous pasty mass. The black schist vary in 
character. This is due largely to the greater or less admixture 
of grit and conglomerate. The rocks of the series vary from 
coarse quartzose conglomerate to a fine grained schist. The 
