Proc. Boy. Soc. Edin.] 
[Vol. XXXII. 
Fig. 1. — Glaciated Boulder of dark Silurian Shale. (Nat. size.) 
Fig. 2. — Glaciated Boulder of fine-grained Silurian Greywacke. (Nat. size.) 
Dr B. N. Peach. 
[Plate I. 
