No. 381.] A HALF-CENTURY OF EVOLUTION. 663 
Cretaceous. In Eurasia, as Kayser states, “this was one of 
the greatest changes in the distribution of land and water over 
almost the whole earth, that is known in geographical history. 
Extensive areas which had for long periods been continents 
were now overflowed by the sea and covered with Cretaceous 
deposits” ; the Upper Cretaceous strata in certain areas in 
Germany and Belgium resting directly on Archean rocks. In 
America (the Dakota stage) there was also a great subsidence. 
The Atlantic coastal plain was submerged over what was Tri- 
assic soil, also the lowlands from New Jersey through Mary- 
land to Florida, while the Gulf of Mexico extended northward 
and covered western Tennessee, Kentucky, and southern Illi- 
nois ; a wide sea connected the Gulf of Mexico with the Arctic 
Ocean, and thus the North America of that time was divided 
into a Pacific and an Atlantic land, the latter comprising the 
Precambrian and Paleozoic areas. 
As Scott states: «The Appalachian Mountains, which had 
been subjected to the long-continued denudation of Triassic, 
Jurassic, and Lower Cretaceous times, were now reduced 
nearly to base-level, the Kittatinny plain of geographers. The 
peneplain was low and flat, covering the whole Appalachian 
region, and the only high hills upon it were the mountains of 
western North Carolina, then much lower than now. Across 
this low plain the Delaware, Susquehanna, and Potomac must 
have held very much their present courses, meandering through 
alluvial flats ” (p. 481). An elevatory movement began in the 
succeeding or Colorado epoch, and this was succeeded by an 
uplift on the Atlantic and Gulf coasts, and the continued 
upheaval in the interior resulted in the deposition of the Lara- 
mie brackish and fresh-water beds. There were similar wide- 
Spread subsidences and upheavals in South America, the 
Andean chain being in large part upheaved at the close of the 
Cretaceous. 
In the Cretaceous period there were such differences in the 
distribution of the fossils as to lead Römer, from his explora- 
tions in Texas as early as 1852, to consider that the resem- 
blance of the fossils of Texas, Alabama, and Mexico, with the 
West Indies and Columbia, to those of southern Europe, were 
