Proc. Roy. Soc. Edin. ] 
[Yol. XXXII. 
Rolled Pebbles a little less than natural size. 
Figs. 1, 2. — Silurian Greywacke. Fig. 3. — Encrinital Limestone (Carboniferous). 
Fig. 4. — Chalk Flint. Fig. 5. — Vein Quartz. Fig. 6. — Dolomite. 
Dr B. N. Peach. 
[Plate II. 
