“aoe ON THE GEOLOGY OF THE ISLAND OF AQUIDNECK, 
depth may sometimes be connected with a variation in the hardness _ 
of the material in which the excavation is made.* att 
Since the formation of these depressions a considerable amount 
_ of filling has been going on which has doubtless done much to 
modify the form of the bottom and diminish its depth. There an 
not expressly made for’ that purpose, the diagrams also show that 
the land surfaces are considerably more irregular than those 
caused by water; water action when the land is buried beneath it 
effect when it acts upon the land lands. There are reasons N 
believe that the channels to the east and west of the island were 
occupied by distinct glacial streams for a short period towards the 
close of the last ice time. The duration of these local glaciers 
must have been short, inasmuch as the distinct termina lor lateral 
moraines are few and indistinct. m 
Excepting the extreme ends of the island the topography is of the 
simplest character; the broad valleys have slopes of rem eal 
similarity showing that the material in which they are excavated 
must have a tolerably uniform consistency. The extreme sonièr 
west and northeast ends of the island have contours which 
trast remarkably with the middle region. The region £no 
the neck, lying just south of Newport and the harbor thereof 
one of the most irregular surfaces in New England. A 
sight it seems a mere confusion of ice-worn rocks and tra 
masses piled without order. A little examination shows, 
that here too we have a set of valleys which have à | 
‘north and south course, the sides and bottoms of which gre 
worn into the irregular shapes, which give the chaotic look 
surface, by the action of the flowing water and the old 
The rock being of very varied hardness has worn wit 
how: 
mation, materials as homogeneous as the others are Vé 
homogeneity in the character of the latter rocks has © 
*The great valleys which now form the Bay were doubtless wee sia 
cant troughs of small streams which have been developed under te ©” 
indicated. 
5 
t These diagrams will be gi in the next number of this Journal. 
