PLATE. H 









DIAGRAMS OF SEA-URCHIN EXCAVATIONS AT BIARRITZ, 
(JULES MARCOU, DEL.) 
A few words in explanation of the diagram may lead to a better comprehension of 
ig. 1 represents a pot-hole partially filled with water, on the walls of which sea- 
in a ring. e 
m appear the small stones, (c), which are supposed to form the annular depression 
h 
about the style (s) ; B of Fig. 4 represents the ring of sea-urchins on the surface of the 
rock, seen from above.—(See page £3. 
