A CONTRIBUTION TO THE ZONING OF THE SHORE. 



BY JAMES HORNELL. 



The zoning of the littoral of the south coast of Jersey, has of 

 late attracted much of my attention. Here, owing to several physical 

 causes, the conditions of life are most peculiar. The tide has a rise of 

 fully 40 feet at certain times ; the littoral is extremely broad and 

 diversified — two miles of rugged reefs, rock-pools, gullies, and zostera 

 banks, often intervening between high and low water marks ; life 

 competition is wonderfully keen, and the variety of this life is 

 immense ; finally, the mildness of the climate and the balmy warmth 

 of the Gulf Stream waters that impinge on the coast, have stim- 

 ulating effects upon the littoral life that can with difficulty be 

 adequately appreciated by those not intimately acquainted with such 

 influences. 



Undoubtedly the most conspicuous instance of zoning is afforded 

 by the olive-green (brown) seaweeds. On this coast they furnish well 

 marked regions, and in descending order are : — 



1. Zone of Fucus canaliculatus, some four to five feet broad — the 



upper edge not covered at high water of neap tides. 



2. Zone of Fucus vesiculosus and F. platycarpus, extending from 



the lower edge of the preceding to half-tide mark. 



3. Zone of F. nodosus, from half-tide down to five feet above 



low water. 



4. Zoue of F. serratus — the five feet above low-water mark, where 



F. serratus grows tvitJiout intermingling of other species. 

 It is also found as far up as half- tide, mingling ivith 

 F. nodosus, whose zone it thus overlaps. 



5. Zone of Laminaria, extending downwards from low water, with an 



average breadth of 25 to 30 feet. 



Another distinct set of zones on this coast is made thus : — 



1. Balanus zone. The barren region covered with innumerable 



B. balanoidcs, lying between high water mark of spring and of 

 neap tide. 



2. Limpet zone. Somewhat overlapping the lower edge of the 



Balanus region, and ranging downwards to low water; the 

 limpets grow very scarce as the Laminarian zone is approached. 



3. Haliotis zone. Almost equivalent with "Laminarian zone." 



Characterized by the presence of the magnificent gastropod 



Haliotis tuberculata. 

 Sars and Loven and others intercalate a fourth zone, that of the 

 pink seaweed Corallina officinalis, between 2 and 3, giving in descend- 

 ing order: 1, Balanus; 2, Limpets; 3, Corallina; 4, Laminar ia: 



