13. RYE TOWNSHIP. F 2 . 307 



obtained it appears probable that these shales once existed 

 in full mass and that they were afterwards eroded. Careful 

 and minute examination of the beds in the Polecat valley 

 can alone remove all doubt and such examination will require 

 more time than could now be afforded. On the result de- 

 per ds the decision whether Rye township was really elevated 

 above the sea at the time in question or existed as a low 

 sand bank washed and often covered by the waves. It may, 

 however, be safely asserted that whether dry or only a salt 

 marsh it lay so low that the erosion from its surface was 

 not great or rapid. Its comparatively small amount war- 

 rants another inference — that Rye township was above the 

 sea only during part of the interval in question, that is, the 

 interval that elapsed from the deposition of the Onondaga 

 variegated shale to that of the Hamilton sandstone. If, as 

 maintained above, the gray shales were deposited, the town- 

 ship must have been below sea level at the time. It must 

 then have risen to or above that level and remained so while 

 they were destroyed. Furthermore their destruction must 

 have occupied the whole lapse of time until it again sub- 

 sided, that is the whole interval during which the missing 

 rocks were deposited elsewhere. Now as the thickness of the 

 Onondaga shale removed cannot be estimated at more than 

 300 or 400 feet, and as the material was doubtless as soft as 

 it is now it is evident that erosion was not violent — an in- 

 direct proof moreover that the land was low because erosion 

 increases at a high rate with elevation. 



It follows, therefore, that the dry or nearly dry area in 

 Rye township only existed during the latter part of the 

 time represented by the gap above pointed out in the geo- 

 logical record. For to maintain that the ground was dry 

 during the w 7 hole interval would be, as shown above, to 

 maintain that the forces of erosion did nothing — that they 

 were in abeyance — a geological absurdity. We may then 

 divide the interval into two equal parts and assume that 

 the work of erosion during the latter half of the time pro- 

 ceeded as fast as the work of deposition during the former. 

 We then reach the intelligible and defensible position that 

 Rye township was above the sea during the latter half of 



