Page:The New International Encyclopædia 1st ed. v. 05.djvu/659

* CKETACEOXJS SYSTEM. 567 CRETE. times an luiconlorinity between the Upper Cre- taceous and the Kocone, or lower member of the Tertiary, especially in the United States. The classitication of the Cretaceous jiresents many diUiculties, owing to the variable section which it exhibits in dilVerent areas; but European and American geologists arc agreed on a division into an upper and a lower member, while for divisions of lesser size local names are employed. The Lower Cretaceous is represented in the northern Ciulf States by (a) Tuscaloosa and (b) Eutaw stages: in Texas and the western Gulf borders by (a) Trinity, (b) Fredericksburg, and (c) Washita stages. The Upper Cretaceous in the Rocky ilountain region has the following subdivisions: (a) Dakota stage, (b) Benton stage, (c) Niobrara stage, (d) Pierre stage, (e) Fox Hills stage, (f) Laramie stage; while in the Atlantic border States it is divided into (a) Raritan stage and (b) New Jersey Greensand stage. The Cretaceous rocks of North America form a belt of incre.asing width, extending south- ward along the Atlantic coast from New York, through New .Jersey, JIaryland. North Carolina, Georgia, and Florida : then around the northern and western shores of the Mexican Gulf, up the Mississippi Valley to the mouth of the Ohio, and from Texas northward to the foothills of the Rocky ^Mountains. They occur also in Nebraska, Kansas, and Iowa. The greatest development of the Cretaceous system is in Wyoming, Utah, Colorado, and west of the Sier- ra Nevadas in California. In some portions of these last-named regions it is found at heights of 10,000 and 12.000 feet. It occurs also in Arctic America, near the mouth of the Mackenzie River. The American Cretaceous beds consist of greensand — called also 'marl,' and much used in New Jersey and elsewhere for fertilizing land — sands of other kinds, clays, shell deposits, and, on the Gulf of Mexico, especially in Texas, lime- stone. In New Jersev the formation is 400 or 500 feet thick; in Alabama, 2000 feet; in Texas, 800 feet, chiefly solid limestone ; in the upper Missouri basin more than 2000 feet ; and east of the Wasatch, more than 9000 feet. The rocks of the Cretaceous contain an abim- dance of both animal and plant remains, for this was a closing period of an era in which reptiles predominated, and, curiously enough, but few or none of the Cretaceous species have continued into the Tertiary. The plants found in the Cre- taceous represent angiosperms, which were not found before this era, both dicotyledons and palms, the former including species of the oak, willow, poplar, beech, maple, fig, tulip, sassafras, eucalyptus, and sequoi.i. Many palms and cycads are found in the Cretaceous of North America. The appearance of the dicotyledons in this for- mation is rather sudden. The animal remains found include both the smallest and largest forms. There are foraminifera, sponges (whjch were very common in the chalk). eehinoids, many mollusks, especially spirally coiled ammonites, and oysters. The fishes show a continuation of the placoids and ganoids of the former era ; but teleosts, or true bony fishes, made their first ap- pearance. There was also an extraordinary abundance of reptiles, including enaliosaurs, dinosaurs, pterosaurs, and crocodiles. Some of the pterosaurs from the Kansas rock meas- ured from 20 to 25 feet in expanse of wing. The sea-saurians were from 10 to 50 feet l.mg. Cope describes the elasmosaurus as a snake-like form 40 feet long, with an arrow- shaped head on a swan-like neck that rose 20 feet 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 sea- serpents. More curious still were the birds with teeth, found in New Jersey and Kansas. (See IcilTiiYouxi.s.) The mammalian remains were mostly those of lower orders, such as marsupials and monotremes. The geographic developments in North Amer- ica during the Cretaceovis were great. The in- terior continental sea was shallowed, and finally obliterated by the uplifting of the land, so that the eastern and western portion of the L'nited States were joined into one continent. This up- lift became emphasized toward the end of the Cretaceous, when the Rocky Jtountains were formed. Violent volcanic eruptions accompanied this iiplift, and the lava-flows of the Yellowstone regions dale from this time. The economic products include most of the coal and lignite deposits of the Western States, ilanj- of the gold and silver bearing fissure veins of the Rockies were formed in the Creta- ceous, while other ])roducts are fire-clays, chalk, greensand, and iron ores. In Europe the Cretaceous rocks assume great importance. According to Geikie, they may be grouped into two fairly distinct areas, of which the northern includes Great Britain, the low- lands of central Euro])e, with portions of Silesia, Bohemia, and northern France ; while the south- ern embraces the central and southern part of France, the Alps, and the Mediterranean basin. The northern area is characterized by shallow- water deposits — sandstones, conglomerates, and marls — more or less glauconitie, and passing into a loosely textured limestone or chalk. In the southern basin the typical rocks are massive, compact limestones, which indicate conditions of deeper water and freer communication with the open sea. The entire series of rocks is usu- ally grouped by geologists as follows : Lower Cre- taceous — (a) Neocomian, (b) Urgonian, (c) Aptian; Upper Cretaceous — (a) Gault or Albian, (b) Cenomanian. (c) Turonian, (d) Senonian. (e) Danian. The dividing line between the Upper and Lower Cretaceous is regarded by the French geologists as occurring at the top of the Albian. The most conspicuous member of the Cretaceous is the white chalk (Upper Creta- ceous) which forms the remarkable cliffs of southeastern England and northwestern France. Consult Dana, Mnitual of Geology (4th cd.. New Y'ork, 1S90) ; Geikie, Text-Book of Geol- ogy (London, 189."?) : White, "Correlation Papers, Cretaceous," United States Geological Survey, Bulletin S? (Washington, 1S91). CRETE (Lat. Creta, Gk. Kpi/r,/, Krete, NGk. Kpln, Kiili. Turk. Kirit). or Candi.i. An island in the Mediterranean, situated south of Greece, considered the most sontherlv part of Europe. It lies between latitudes 34° .57' and 35° 41' N., and between longitndei 23° 30' and 2(i° 20' E. (Map: Greece, Ft!). It is oblong in shape, hav- ing a length of about 1.50 miles, and varying from' 6 to 35 miles in width, with an area of 3326 square miles. Its mountainous surface bears some resemblance to that of Greece. The western part of the island is the more elevated, and con-