720 



/. HOWARD WILSON 



(Balanus portalus); numerous perfect, small shells and sub-angular 

 pebbles. 



No. 15. — Mussel bed; normal beach sand, in places crowded 

 with fragments of Modiola, and containing complete small shells 

 of other genera. The mussel shell fragments are generally worn; 

 Balanus fragments also common; perfect Astarte found, and more 

 or less fragmentary Lunatia heros, and Venus shells ; fossils like those 



Fig. 6 



found in Nos. 12, 13, 14, but not so numerous. The upper layer 

 is marked by rounded pebbles, generally small, . but occasionally 

 gem - n dj ame ter; pebbles sometimes occur in the mussel layer of 

 lower part of bed. Some of the purer layers of sand are pink, 

 rarely yellow. 



No. 16. — Pure quartz sand, of varying grain, stratified and well 

 assorted; grains all rounded and opaque, as if sand had been wind- 

 blown before deposition; some fine streaks, almost like rock-flour, 

 which show as very fine sand grains under microscope, and contain 



