RAMBLES OF A GEOLOGIST. 3-43 



yellow sponge, the Halichondria papillaris, remarkable 

 chiefly for its sharp siliceous spicula and its strong phosphoric 

 smell ; and the characteristic vegetable is the smooth-stemmed 

 tangle, or queener. In yet another zone we find the common 

 limpet and the vesicular kelp-weed ; and the small gray ba- 

 lanus and serrated kelp-weed form the productions of the 

 top. We may see exactly the same zones occurring in broad 

 belts along the shore, each zone indicative of a certain over- 

 lying depth of water ; but it seems curious enough to find 

 them all existing in succession on one boulder. Of the boul- 

 der and its story, however, more in my next. 



