NOTES ON MARINE DEPOSITS OF THE FIRTH OF FORTH. 221 



At several points over the area of each of these stations, besides 

 numerous points outside these areas, samples of the deposits were 

 obtained by sounding tube or dredge. In many cases fully one 

 hundredweight of the deposit came up, which was submitted to 

 careful washing on the spot through sieves of various material 

 and size of mesh ; all the animals noted and preserved, as also 

 those taken by the beam trawl and tow-nets ; the microscopical 

 organisms collected and preserved for further examination, while 

 good typical examples of the deposits, were carefully preserved 

 and brought on shore for detailed examination and microscopical 

 analysis. This work, which required a considerable amount of 

 time and careful manipulation, has been accomplished by myself 

 from time to time, as circumstances would permit. 



The methods employed in the examination of these deposits are 

 the same as those apphed by Messrs. Murray and Ronard in 

 describing the marine deposits obtained during the " Challenger " 

 Expedition. The carbonate of calcium was determined by 

 estimating the carbonic acid, weak and cold hydrochloric acid 

 being used for the purpose. Tlie part insoluble in the acid is 

 designated residue, which, by washing, decantation, and micro- 

 scopical inspection, is separated into three parts — (a) Minerals, the 

 contraction m. di., indicating the mean diameter in millimetres ; 

 (b) Siliceous organisms, including the casts of Foraminifera and 

 other calcareous organisms ; (c) Fine washings, including those 

 particles which, resting in suspension, pass off with the first 

 decantations. 



The numbers in brackets (20-00 per cent.) indicate the per- 

 centage of CaCo3 of the whole sample. 



ClASSIFICATION AND GENERAL CHARACTER OF THE DEPOSITS 

 OF THE FiRTH OF FORTH. 



The deposits found in the area under consideration come under 

 the classification of shallow-water terrigenous deposits*, and are, 

 as would be expected, of a true terrigenous character. They 

 are mainly made up of the ddbris derived from the general 

 disintegration of the land along the shores of the estuary and 

 coast of the firth, from land drainage, and by solid matter borne 



* After Messrs. Murrav and Ronard. 



