98 PRINCIPLES OF STRATIGRAPHY 



109. WILLS, LEONARD J. 1910. On the Occurrence of Wind-Worn Peb- 

 bles in High-Level Gravels in Worcestershire. Geological Magazine, 

 Decade V, Vol. VH, pp. 299-302, pi. XXV. 



no. YOKOYAMA, MATAJIRO. 191 1. CHmatic Changes in Japan Since 

 the Pliocenic Epoch. Journal of the College of Science, Imperial Uni- 

 versity of Tokyo, Vol. XXXII, article V, October, 191 1. 



111. ZITTEL, KARL A. VON. 1883. Beitrage zur Geologic und Palaeon- 



tologie der libyschen Wiiste. Palaeontographica, Vol. XXX, pp. 

 I-CXLVIL 



Supplementary. 



112. HUMPHREYS, W. J. 1913. Volcanic Dust and other factors in the Pro- 



duction of Climatic Changes, and their possible Relation to Ice Ages. 

 Bulletin of the Mount Weather Observatory, Vol. VI, pt i, W. B., No. 

 511, pp. 1-34- 



