752 DYNAMICAL GEOLOGY. 



gone any uplifting from force below. But, however this may be, the 

 region actually experienced elevation before the Triassic period opened, 

 as is proved by the position of the Triassic beds ; and this took place 

 through a gentle upward bending of the crust, such a bending becom- 

 ing possible after (although not before) the region of the Appalachi- 

 ans had become a portion of the stable part of the coutinent. 



The Rocky Mountains in the Cretaceous era were 10,000 feet be- 

 low their present level, the sea covering them. They were raised as 

 a whole, during the Tertiary, through a low geanticlinal. The last 

 bendings were more local than the preceding, because the crust had 

 become stiffened by its plicated and solidified, and partly crystallized, 

 coatings, as well as by thickening beneath ; and, therefore, while the 

 Tertiary movements were in progress, the part of the force not ex- 

 pended in producing them carried forward an upward bend, or geanti- 

 clinal, of the vast Rocky Mountain region as a whole. 



11. Anticlinoria of the Atlantic Border of North America. — An 

 upward bend of the crust, or geanticlinal, is of itself an elevation ; and 

 such an elevation is an anticlinorium. The Cincinnati uplift, described 

 on page 217, is an anticlinorium, made, parallel with the Appalachians, 

 after the Lower Silurian era, cotemporaneously with the making of 

 the Green Mountains. 



While the geosynclinal preparatory for the making of the Appala- 

 chians, and those for the Triassico-Jurassic formations, were going for- 

 ward, through Paleozoic and Mesozoic time, there was, along the At- 

 lantic Border, near or outside of the present coast-line, a geanticlinal 

 in progress, or sea-border anticlinorium. It was the first effect of the 

 pressure from the ocean-ward ; and the geosynclinal was the second. 



Proofs of this are found (1) in the necessity that one movement should have taken 

 place as a counterpart to the other, since the depression of a geosynclinal thousands of 

 feet would push out from beneath it an equivalent mass of plastic rock; and this would 

 involve a bulging on one side or the other; (2) in the fact that obliquely-upward pressure 

 from the ocean-ward, however slight the obliquity, would first have made an upward 

 bend, and beyond this the downward bend; and (3) in the . character of the remains of 

 marine life, or else its absence, in the sea-border rocks, through a large part of Paleozoic 

 and Mesozoic time, showing that a barrier of some kind existed along the sea border. 



The facts from the fossils are these : While, in the early part of the Lower Silurian, 

 the species of the eastern border are like those of Europe in some points, this is not so 

 in the long Trenton period, so that the barrier must then have existed (page 250). In 

 the Carboniferous rocks of eastern Pennsylvania, there are almost no marine fossils; 

 and again, in the following Triassic and Jurassic eras, none at all. It was not until the 

 Cretaceous period that the coast was open to the ocean, through a disappearance of the 

 geanticlinal barrier. The Cretaceous rocks abound in marine fossils. 



Anticlinoria appear generally to have faded out, as gravity was against their perma- 

 nence; and that in the region of Cincinnati, extending southwestward to Tennessee, i; 

 one of the few permanent ones. 



12. Geanticlinal Effects over the Continents, greatest and most per- 

 manent, and Geosynclinal least so, in the Tertiary and Quaternary 



