146 



EARTH FEATURES AND THEIR MEANING 



Another important feature resulting from denudation is the 

 Mesa or table mountain with its protecting basalt cap above softer 

 rocks. Its profile most resembles that of table mountains due to 

 differential erosion of alternately strong and weak horizontally 



FIG. 154. Character profiles connected with volcanoes. 



bedded rocks, such as compose the upper portion of the section in 

 the Grand Canon of the Colorado. Here, however, in place of a 

 single unusually strong top layer there are found several strong 

 layers in alternation with weaker ones so as to produce additional 

 steps in the profile. 



READING REFERENCES TO CHAPTERS IX AND X 

 General works : 



PAULETT SCROPE. The Geology of the Extinct Volcanoes of Central 

 France. John Murray, London, 1858, pp. 258. (An epoch-making 

 work of early date which, like the following reference, may be studied 

 to advantage to-day.) 



SIR CHARLES LYELL. Principles of Geology, vol. 1, Chapters xxiii-xxv. 



MELCHIOR NEUMAYR. Erdgeschichte, vol. 1, Allgemeine Geologie, revised 

 edition by v. Uhlig, 1897, pp. 133-277 (a storehouse of valuable infor- 

 mation clearly presented). 



J. D. DANA. Characteristics of Volcanoes, with Contributions of Facts 

 and Principles from the Hawaiian Islands. Dodd, Mead, and Com- 

 pany, New York, 1890, pp. 397. 



TEMPEST ANDERSON. Volcanic Studies in Many Lands, being reproduc- 

 tions of photographs by the author with explanatory notes. John 

 Murray, London, 1903, pp. 200, pis. 105. 



T. G. BONNEY. Volcanoes, their Structure and Significance. John 

 Murray, London, 1899, pp. 331. 





