122 Mr John Eattray 07i the 



On the AUjce of Granton Quarry. By John Eattray, M.A., 

 B.Sc, Marine Station, Granton, Edinburgh. 



(Read July lOtli 1884.) 



In this quarry a well marked division of the tidal belt into 

 zones, each bearing a preponderance of certain species, is to be 

 observed. We may enumerate these zones as follows : — 



1. The upper tidal zone, characterised by its abundant 

 growth of Entcromorpha compressa and E. intestinalis — both 

 of which species are especially common on the landward 

 side of the quarry, although very rare on the seaward side, 

 which has an exposure to the south. 



2. The median tidal zone, in which very few Chlorosperons 

 are to be found, but which is marked out by a great development 

 of Fuci, especially Eucus platycarpus and E. nodosus, as well as 

 by the occurrence of many JRhodospermic Ceramiums. 



3. The lower tidal zone, in which we again find a very 

 great development of Entcromorpha comjjressa with Ulva linza 

 growing around its lower margin. 



4 The aqueous zone, which is always under water, and 

 where one finds a few delicate Callithaiiinia, Ectocarpii, and 

 Laminaria saccharina* 



While the various belts thus pointed out are very readily 

 distinguishable from one another, probably the fact of greatest 

 immediate interest is the disappearance of Laminaria sacchar- 

 ina, which has occurred consequent on a lowering of the low 

 water-level of the quarry, which was affected some time ago, 

 in order to allow the steam-yacht connected with the marine 

 station to enter the quarry from the river at high tide. A 

 passage was cut through a bar of shingle and boulders to a 

 depth of several feet, and the result has been that the large 

 leaf-like thalliof the Laminaria have fallen from their attach- 

 ment wherever that attachment was effected in the zone which 

 is now periodically exposed to the air, but which was formerly 

 invariably under water. It is to be noted, however, that this 

 species of Laminaria has not entirely disappeared from the 

 quarry; it is still to be found on the rocks which are not 

 exposed to the air at every low tide, and also on cages which 

 are buoyed in the quarry, and in which zoological specimens 

 are kept alive. 



* Mem. de VAcad. d. Set, 1845, Bd. 337/. 



