436 C. SCHUCHERT PALEOGEOGRAPHY OF NORTH AMERICA 



Berkey 21 has given two maps showing the position of Mississippian sea 

 during "mid-Saint Peter time" and at the "close of Saint Peter time." 

 Grabau 22 shows one map of Cambric and four maps of Ordovicic time in 

 Xorth America. G. F. Matthew 23 portrays two maps — one of Lower Hu- 

 ronian, the other of Siluric time. W. D. Matthew 24 presents six good 

 Tertiary paleogeographic maps of the world. Schuchert 25 published two 

 Middle Devonic maps of eastern United States, and in 1908 26 presented 

 three paleogeographic maps of the Xorth American Devonic. Scott 

 brought out eight paleogeographic maps of North America in his "An 

 Introduction to Geology," 1907. Weller 27 indicated on two maps the prob- 

 able shorelines within the United States of the latest Devonic and Osage 

 of Mississippic time. The same paleontologist 28 published two excellent 

 maps of the American Siluric shorelines and the Arctic path for these 

 European faunas. Williams 29 presents a "chart showing the approximate 

 position of the Devonian intercontinental sea." Veatch 30 exhibits ten 

 maps of the land and water areas in the south-central United States dur- 

 ing Cretacic and Tertiary times. Clarke 31 gives two Lower Devonic maps 

 of Xew York. 



RfiSUMS 



By tabulating these maps, it will be seen that since 1863 no less than 

 306 different paleogeographic maps have been published, of which 151 

 relate more or less directly to North America. These maps are as yet 

 highly hypothetical, this being particularly true of world maps. 



The changes wrought in these maps are fundamental. Instead of the- 

 "universal oceans" of the older maps, modern ones show much smaller 

 and more local seas, separated from one another by land barriers. Also 

 may be noted the irregular emergence of local lands that are repeatedly 

 submerged, the general tendency, however, being toward more stable conti- 

 nents and oceanic basins. The local seas, first mapped by Heer, may be 

 seen to best advantage in Lapparenfs most valuable Traite. Very few of 

 the maps, however, as yet clearly differentiate between marine and conti- 

 nental deposits, and by the inclusion of both as marine deposits the con- 



21 Berkey : Bull. Geological Society of America, vol. 17, 1906, pp. 248-249. 



22 Grabau : Journal of Geology, Chicago, vol. 17, 1909. 



23 G. F. Matthew : Bull. Natural History Society of New Brunswick, vol. 6, 1908. 

 2i W. D. Matthew : Bull. American Museum of Natural History, vol. 22, 1906. 



25 Schuchert : American Geologist, 1903. 



23 Schuchert in Eastman, Iowa Geological Survey, Ann. Rep., vol. 18, 1908. 



27 Weller : Journal of Geology, Chicago, vol. 6, 1898, pp. 307-308. 



28 Weller: Ibidem, 1898, pp. 697, 699. 



29 Williams : American Journal of Science, vol. 3, 1897, p. 395. 



30 Veatch : Professional Paper, no. 46. U. S. Geological Survey. 1906. 



31 Clarke : Memoir no. 9, New York State Museum, 1908, pp. 8-9. 



