13 



beds have a dip which, if persistent, would bring them under 

 undoubted Cambrian beds at a few miles distance. 



At the same time, I can scarcely see how the beds in ques- 

 tion can be referred to a Pre-Cambrian age, as the inclusions of 

 sedimentary rocks, such as quartzites, metamorphic shales, and 

 limestones among the erratics, demands a pre-existing sedi- 

 mentary series from which they have been derived, and w^hich 

 may be assumed to be of Archaean age. This discovery marks, 

 so far as i am aware, the first observation of a Cambrian gla- 

 cial age in the Southern Hemisphere, and is probably the most 

 extensive exposure of its kind in any part of the world. 



I have to express my great indebtedness to Mr. John 

 Heithersay, who, from his intimate knowledge of the country 

 around Mount G-raing'er and Petersburo;, g-ave me verv valuable 

 assistance in carrvinc^ out mv observa,tions in that district. 



