CRETACEOUS SYSTEM (ante), in North America, extends along the Atlantic, s. of New York—where, though mostly hidden by the tertiary formation, it is visible in New Jersey and further s.—around the n. and w. shores of the Mexican gulf, up the Mississippi valley to the mouth of the Ohio, and, on the w., from Texas northward over the sides of the Rocky mountains. Its greatest development is in Wyoming, Utah, Colorado, and w. of the Sierra Nevada in California. In some portions of these ,last named regions it rises to heights of 10,000 and 12,000 feet. It is found also in Arctic America, near the mouth of the Mackenzie river. The American cretaceous beds con sist of layers of greensand—called also marl, and extensively used in New Jersey and elsewhere for fertilizing land--sands of other kinds, clays, shells, and, on the gulf of Mexico, especially in Texas, limestone. In New Jersey the formation is 400 or 500 ft. thick, in Alabama 2,000, in Texas 800, chiefly solid limestone, in the upper Missouri more than 2,000, and e. of the Wahsatch more than 9,000. In Colorado, New Mexico, and Vancouver's island the formation contains important beds of brown coal or lignite. The coal•beds of Wyoming and Utah, and some southward, are regarded by some geol ogists as belonging to this formation; others assign them to the tertiary age. Among American cretaceous fossils are included 100 species of the earliest dicotyledonous plants yet found on this continent, half of which are allied with living American forms. Among them are species of oak, willow, poplar, beech, maple, hickory, fig, tulip, sassa fras, sequoia, American palm, and cycads. Among the molluscs are species of tere bratula, oatrea, gryphaa, inoeeramus, hippuritea, radiolites, ammonites, scapleites, kamites, baculites, belimnites, ancyloceras, and turrilites. Of the fishes of the American cretaceous seas nearly 100 species are known. They include large representatives of modern predatory types like the salmon and saury, together with cestracionts and ganoids. The American reptiles of this period are especially remarkable for their
number, variety, and size. Cope (who includes, however, in his statement the lignite group, which other geologists rank among the tertiary formations) enumerates 18 species of deinosaurs, 4 pterosaurs, 14 crocodilians, 13 sea saurians, 48 testudinates, and 50 sea serpents. Some of the pterosaurs from the Kansas rocks measured from 20 to 25 ft. in expanse of wing. The sea saurians were from 10 to 50 ft. long. The elas mosanrus Cope describes as a snake-like form 40 ft. long, with an arrow-shaped head on a swan-like neck that rose 20 ft. out of the water. Consequently it could swim many feet below, the surface, and yet have its head extended into the air for breath. The American rocks supply 40 species of the sea serpents, some of which were 75 ft. long, with a bead 4 ft. long, and a mouth of enormous size, having 4 rows of immense curved teeth with which to seize their prey and joints in the lower jaw to enable them the better to swallow it whole. In the American portion of this formation, 9 species of birds, have been found. Three belonged to the order of swimmers, which includes modern ducks, geese, and gulls: four were waders, and two, of an order long extinct, resembled fishes and reptiles as well as birds. During the cretaceous period it is sup posed that the Delaware and Chesapeake bays were in the main ocean, that Florida was under water, that the valley of the Missouri was a salt water region, that the Rocky mountains were in great part submerged, and that the gulf of Mexico extended over much of Georgia, Alabama, and Mississippi, northward to the mouth of the Ohio and far on to the n.w., perhaps even to the Arctic seas.