The Making of Pennsylvania. — Claypole. 233 
though seldom brought forward. Such crumpling as above 
described can not have occurred without the wholesale trans- 
fer of large areas of the state from one place to another. The 
folding of the strata in the west lessened their horizontal 
extent and with every succeeding anticlinal to the east this 
shortening of area became greater so that the previous swamp 
was not only thrown into a series of ridges and furrows but 
these ridges and furrows were crowded against one another 
until the whole mass of the southeastern arches was shoved 
bodily forward to the northwest over the deeper rocks below 
it. Careful computation made some years ago by the writer 
showed that the line from a point in Blair county to a point 
in Cumberland county, crossing eleven of the mountain ranges 
and the Great Valley and now only 65 miles long represents a 
line about 153 miles long before compression took place. Or, 
quoting from the paper alluded to : — 
''During the compression and corrugation to which the 
mountains of Pennsylvania owe their origin the southeast line 
of Huntingdon county was moved forward two miles, that of 
Mifflin four miles, that of Juniata six miles, that of Perry 
nine miles and that of Cumberland eighty-eight miles. Con- 
sequently the whole of Mifflin county was shoved at the least 
two miles to the northwest, the whole of Juniata county four 
miles, the whole of Perry county six miles and the whole of 
Cumberland county nine miles, over the underlying deeper 
strata. The movement of course diminished toward the north- 
west in consequence of the increasing resistance offered by the 
increasing load and came at length to nothing beyond the 
limits of Pennsylvania. Ohio was the great buffer-plate 
against which this tremendous Earth-force spent itself. The 
southeastern portion of the district — the Cumberland valley — 
and even probably some considerable area beyond it to the 
southeast felt its first and mightiest pressure. There the 
strata were crumpled, bent, crushed and thereby thickened till 
it became easier to shove them bodily forward than to bend 
them again. They were consequently added as a snow-plow 
in front of the mighty engine and in their turn communicated 
the movement and the crumpling to the northwestern country 
beyond them." ' 
^"Pennsylvania before and after the elevation of the Appalachians." 
American Naturalist, March, 1885. 
