Pennsylvania Geology Final Report Volume 1 1981

NO. IV. IN THE BEDFORD GAPS. 665
berry township, and obscurely at two i:)laces on Bunning's
mountain ; but Oneida beds are certainly absent along the
Raystown Juniata in both Tussey and Evitts mountain
gaps. In fact Oneida sandstone beds were seen by him at
no locality in Bedford county more than 35' thick. At the
two places last mentioned there can be no question of concealment
by faults, for the top layers of No. Ill are regularly
overlaid by Medina red or brownish red shales con-
taining two fossils which unmistakably belong^ to that divi-
sioTi{Ambonf/c7iia radlata and Rhynchonella c«^a;r)and tho
Hudson river slates pass without any break of sequence
upward into Medina sJiales ; so that there can be no doubt
that the Oaeida formation was not deposited in the bed of
the sea in this locality, even in the condition of fine sand.
Yet it must not be rashly concluded from this fact, that
dry land existed here. For had dry land existed it must
have been land of No. Ill raised above the sea level and
afterwards submerged to receive the deposit of No. lY.
But the moment a portion of sea bottom is lifted above
water level rain-erosion commences, and continues until re-
submergence ; and rain-erosion must leave its marks in the
shape of hills and hollows however small or low. Some
break in the continuity of the deposit must take place, and
must remain visible ever after wherever the consolidated
rock strata are now exposed to examination. If no such
break appears we may be sure that the sea bottom has not
been lifted to the air. Therefore if the Oneidaformation.,
thick and pebbly further northeast, grows thinner and finer
and at length disappears going south, allowing the J/ecZma
above it and the Hudson river below it to come quietly
together, it is certain that its disappearance is really and
surely due to the fact that tlie sediments were floated further
out into deep water according to their fineness, until
at length the finest material was exhausted, or, mingled with
equally fine material floated in from other directions.