2o8 PRINCIPLES OF STRATIGRAPHY 



43. WALTHER, JOHANNES. 1900. Das Gesetz der Wustenbildung, First 



Edition. Jena. 



44. WALTHER, JOHANNES. 1912. Ibid. Second Edition. Leipzig. 



45. WOODWARD, R. S. 1890. Communication on the Depth of Frost in 



the Arctic. In Russell, Bulletin of the Geological Society of America, 

 Vol. I, pp. 130-132, 



