74 TJie American Geologist. August, i898 
above the river, spreading- irregularly over an area of several 
rods. It shows plainly the structure of a sedimentary rock, 
with oblique stratification and banding, having an observed 
thickness of not more than ten feet. It lies on a coarser con- 
glomerate or breccia, the general structure and dip being such 
as to throw them both below a great thickness of other igne- 
ous beds consisting of alternating trap and amygdaloid. The 
lower or conglomeratic portion of this fragmental is made up 
of large and small masses of trap, sometimes amygdaloidal and 
sometimes massive, having an observed thickness between 30 
and 40 feet. This might easily be mistaken for a rough con- 
dition of the trap of the country, brecciated, etc., but there is 
more or less of the rock (2129) above described disseminated 
through it, indicating the action of oceanic and detrital forces 
during its accumulation. In other words, this coarse trap- 
boulder rock is of the nature of a conglomerate and lies be- 
low other trap beds. 
3. Seeking evidence of the thickness and the extent of 
this lower conglomerate, we found a similar rock at one block 
west of the public school house, where only the fine-grained 
aspect is seen, and where it appears as if it had been broken 
mechanically and recemented by its own debris, making a 
fine-grained, nodular, hard rock, which rises three or four 
feet and is exposed about 20 feet east and west. A thin sec- 
tion of this rock shows essentially the same characters as that 
at the corner of Government and West streets, except that it 
contains more secondary silica and less epidote. In it are 
also developed acicular actinolites which lie in the position 
and have the form of wheat-sheaves, their extremities fraying 
and spreading out. That this structure here is due to sec- 
ondary growth under the action of dynamic or some other 
force is evident, for these actinolite bundles lie in and pene- 
trate secondary granular quartz, the fibres running frequently 
from one grain into another, or even piercing several grains. 
We saw no further exposure of this conglomerate until 
we descended the hill southwardly to the railroad. Here 
can be seen both conglomerates. The upper one rises in a 
blufif where Upper Cambrian fossils are found in a dolomitic 
cement embracing boulder masses of trap, and the lower one 
is seen in the lower portion of the bluff and in a more limited 
