212 ILLINOIS ACADEMY OF SCIENCE 



The whole comprises an area of about 130,000 square miles, 

 an area almost equal to that of Ohio, Indiana and Illinois. 

 (134,000 square miles.) About 45,000 square miles of this 

 is in Arizona 3 , a similar area in Utah, about 20,000 in 

 New Mexico, and about 15,000 in Colorado. Powell in 1879, 

 impressed more by the depth and ramifications of the canyons, 

 applied the descriptive term of "Canyon Lands" to the more 

 dissected part. These names suggest the chief characteristics of 

 the region, great elevation, general horizontality of the strata, 

 and an unusual development of canyons. The name "Colorado 

 Plateaus" 4 in more recent literature is descriptive of the di- 

 visions of the main plateau into many minor natural units. 



The Mesa Verde, one of these units, is located on the ex- 

 treme eastern boundary of the Plateau Province in southwest- 

 ern Colorado. It is cut off from the main plateau by the 

 Rio Mancos Canyon which forms the southeastern and south- 

 ern boundary. The mesa terminates elsewhere in an abrupt 

 escarpment, 1,000 to 1,500 feet high, overlooking the so- 

 called Montezuma Valley which separates it from the Ute 

 mountains on the west, and the Dolores Plateau on the north. 

 To the northeast, close by, are the LaPlata Mountains. The 

 mesa has an area of about 200 square miles and is fairly well 

 known because of its ethnic interest. A part of it was 

 set aside by an act of congress in 1906, establishing the Mesa 

 Verde National Park, "for the preservation from injury or 

 spoilation of the ruins and other works and relics of prehistoric 

 or primitive man. 6 " This paper deals primarily with this 

 area set aside as a national park. 



Although the general characteristics of the mesa are best 

 understood in its relationship with the larger plateau, the more 

 special features, however, are due to local conditions. One of 

 the most prominent of these is the extremely variable semi- 

 arid climate. The mesa is sufficiently near the La Platas to 

 get enough precipitation to support a shrubby growth of oak, 

 pinyons, and cedars ; and thus the name Mesa Verde was ap- 

 plied because of the contrast with the more desert region to 

 the south and west. However, the contrast with the lower 



2 &econd Ann. Rep't. U. S. G. S., p. 50, (1880-81). Sixth Ann. Rep't. U. S, G. S., 

 pp. 114-117 Pis. 11 and 12 (1884-5). 



"Robinson, P. P., 76, U. S. G. S. p. 13. 

 *Bowman, I. : Forest Physiography, p. 256. 

 "Rep't. of Sup't., 1913, p. 11. 



