5 6S 



POPULAR SCIENCE MONTHLY. 



make their way to this sea-washed platform. On the sea face the rock, 

 which is an seolian limestone, is slightly raised above the general 

 level of the floor, and is overgrown with nullipores and other corallines, 



Fig. 25. The 'Intrepid.' From a photograph by L. J. Cole. 



as well as non-calcareous algae; and here serpulas, millepores and 

 porites abound. Even at low tide this rocky platform is barely above 

 water, and it is so honeycombed and porous that its surface is very 





Fig. 20. North Rocks. From a photograph by Phelps Gage. 



irregular. The flatter portions are covered here and there with patches 

 of the curious Zoanthidse. There are innumerable pools and channels 

 all showing the greatest variety of color in the plant and animal life 

 that clothes their sides and bottoms. Here in the pools and passages, 



