Geology by Submarine Researches* 319 



and to their mutual connection, must lead to results still 

 more important than those which have been obtained, I have, 

 for several years, conducted submarine researches by means 

 of the dredge. In the present communication, I shall give a 

 brief account of some of the more remarkable facts and con- 

 clusions to which they have led, and as briefly point out their 

 bearings on the science of geology. 



I. Living beings are not distributed indifferently on the bed of 

 the sea, but certain species live in certain parts, according to the 

 depth, so that the sea- bed presents a series of zones or regions, 

 each peopled by its peculiar inhabitants. — Every person who 

 has walked between high and low water-marks on the British 

 coasts, when the tide was out, must have observed, that the 

 animals and plants which inhabit that space, do not live on 

 all parts of it alike, but that particular kinds reach only to 

 certain distances from its extremities. Thus the species of 

 Auricula are met with only at the very margin of high water 

 mark, along with Littorina coerulescens, and saxatilis^ Velutina 

 Otis, Kellia rubra, Balani, &c. ; and among the plants, the yel- 

 low Chondrus crispus (Carrigeen, or Iceland moss of the shops), 

 and Corallina officinalis. These are succeeded by other forms 

 of animals and plants, such as Littorina littorea. Purpura lapil- 

 lus, Trochi, Actineae, Porphyra laciniata (Laver, Sloke), and 

 Ulvce. Towards the margin of low water, Lottia testudinaria, 

 Solen siliqua, and the Dulse, Bhodomenia palmata, with nu- 

 merous Zoophytes and Ascidian molluscs, indicate a third 

 belt of life, connected, however, with the two others, by cer- 

 tain species common to all three, such as Patella vulgata, and 

 Mytilus edulis. These sub- divisions of the sea-bed, ex- 

 posed at ebb-tide, have long attracted attention on the coasts 

 of our own country, and on those of France, where they 

 have been observed by Audouin and Milne Edwards, and of 

 Norway, where that admirable observer Sars has defined them 

 with great accuracy. 



Now this subdivision of the tract between tide-marks into 

 zones of animal life, is a representation in miniature of the 

 entire bed of the sea. The result of my observations, first 



