246 TRANSACTIONS, NATURAL HISTORY SOCIETY OP GLASGOW. 



Planorbulina mediterraniensiK, Xonionina turgida, Will., f. 1. 



[d'Orbj', f. 1. ,, scop/ia, P. andM., f. 1. 



Truncatidina lohatula, W. and J., r. 1. ,, depresaula, W. and J., 



,, lobatnla var., W. and • [v.r. 1. 



[J., f. 1. ,, slelHgera, d'Orby, v.r. 1. 

 Pidinmdina Karstcni, Kss., r. 1. Opcrculina ammonoides, Gron., f. 1. 



Botalia heccarii, L., abdt. 1. PolystomeUa striato-pxmctata, F. 



„ nitida, Will., f. 1. [and M., f. 1. 



Oypsina inharens, Scliul., v.r. 1. ,, subnodosa, r. 1. 



MARINE DEPOSITS AND THEIR BEARING ON 

 MARINE LIFE. 



It is possible by careful examination of most marine deposits 

 to determine very closely what kind and amount of marine life is 

 likely to be found in any given area over the sea floor. 



It has, therefore, often occurred to me that an examination 

 of the marine deposits round our coasts, and over the areas of our 

 great fishing grounds and banks, would greatly assist in throwing 

 light upon the question as to the cause of the destruction of 

 marine life, the movements and depopulation of fish from our 

 inshore fishing grounds, banks, and estuarian waters, which, it is 

 well known, were at one time thickly populated with abundance of 

 marketable fish, but are at the present time, in some localities, 

 scarcely worth the fishing. 



Under ordinary natural conditions, animal life is usually 

 found plentifully distributed all over these areas, but I have to 

 record here that, so far as the Firth of Forth is concerned, a 

 change of conditions has taken place which is undoubtedly detri- 

 mental to the marine life generally. 



By examination of the deposits and general condition of the 

 ground in these localities, a key to this question is, in my opinion, 

 possible to be found. To carry this out, it is necessary to keep in 

 mind the following chief points : — 



1. The geographical features and position of the area to be 



considered. 



2. The physical conditions ; the amount, condition, and 



number of species of animals found living on the sea 

 floor ; and in the deposits themselves. 



3. The age of the deposits, rate of accumulation, their 



permanency, and in what measure they are affected 

 by wave action and currents. 



