THE THAMES FEOM GUILDFOED TO NEWBTJRY. 47 



thought it very probable that, as Mr. "Whitaker had suggested, the 

 white surface of the quartz-boulder had rested on Bagshot Sand, and 

 the brown side had been in the gravel. As to the age of the gravels 

 he considered that the Upper Hale Gravel was the oldest, and that 

 the Chobham Eidges and Silchester Gravels were probably nearly 

 contemporaneous. 



