Proc. Roy. Soc. Edin. ] 
[Vol. XXXII. 
Fig. 1. — Fragments of Oceanic Pumice rounded by attrition with projecting crystals 
and harder parts. (About nat. size.) 
Fig. 2.— Specimen 1 of fig. 1, enlarged to show crystal of Sanidine. 
Dr B. N. Pea.ch. 
[Plate VIII. 
