_P, Pottsville on the coal-measures; 2, Calciferous formation; 3,
Trenton; 4, Hudson River; 5, Oneida and Niagara; 7, Lower Helderberg;
8, 10, 11, Devonian; 12, 13, Subcarboniferous; 14, Carboniferous, or
coal-measures._
These tremendous changes were caused by a pressure of some kind which
came from the east, from where the Atlantic Ocean now rolls.
"It was due to a _lateral_ pressure, the folding having taken place
just as it might in paper or cloth under a lateral or _pushing_
movement."[2]
"It was accompanied by _great heat_ which melted and consolidated the
rocks, changed their condition, drove the volatile gases out of the
bituminous coal and changed it into anthracite, in some places
altered it to graphite, as if it had been passed through a
furnace."[3]
It also made an almost universal slaughter of all forms of life:
"The extermination of life which took place at this time was one of
the most extensive in all geological history; . . . no fossils of the
Carboniferous formation occur in later rocks."[4]
[1. Dana's "Text-Book," p. 152.
2.
Pages:
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611