of the Fishery Board for Scotland. 



345 



and March I obtained specimens of most diverse colours, from brilliant 

 red to almost milky white, indicating that the spatting period was not 

 confined to the early spring. This conclusion was also supported by the 

 microscopic character and degree of maturity of the ovarian cells. 



III. The Forth Clam Beds. 



In the Forth the common scallop is so plentiful as to form regular beds, 

 the position and extent of which are shown on Plate VIII. , which embodies 

 the results of Mr Scott's and my own dredging operations on board the 

 ' Garland.' The chief bed extends for a distance of about 12 miles, from 

 Inclimickrie on the west to almost Gullane Ness on the east. Its breadth 

 varies much, attaining its greatest dimension about opposite Cockenzie. 

 The northern limit of the bed might be defined by a line drawn from 

 Inchmickrie to the north end of Inchkeith, and continued south-eastwards 

 in a direct course to the West Point of Aberlady Bay. The 3| fathom 

 line from West Point westwards might be taken as the extreme shoreward 

 boundary, but the scallops are more plentiful in the deeper water. These 

 boundaries would give the greatest dimensions of the bed as 12 miles long 

 and about 5 miles in breadth. A glance at the map appended will show the 

 irregular configuration of the scallop-bearing area, and how the bed tapers 

 both at the eastern and western extremities till it is less than a mile broad. 

 Inchkeith divides the beds into a large eastern and a small western por- 

 tion. The eastern portion covers an area of about 20 square miles, the 

 extent of the western area being only a few square miles. Over all this 

 great area scallops are found in great quantities ; but in the second bed, 

 which is much smaller and situated about a mile to the north-east of 

 Inchkeith, the scallops are even in greater numbers associated together. 

 The length of the bed is about two miles, and its shoreward boundary is 

 fully two miles from the shore between Kinghorn and Kirkcaldy. Its 

 western limit is not far distant from the northern boundary of the 

 principal bed. The sudden deepening of the water to the north of the 

 eastern portion of the principal bed, perhaps as much as the comminuted 

 character of the mud, hinders the migration of the scallops in this direc- 

 tion. Scallops flourish best in water from 5 to 12 fathoms deep, so the 

 sudden deepening of the Forth from the gently sloping platform of 12 

 fathoms and less in depth, to a submarine valley of 20 to 30 fathoms, 

 raises bathymetrical obstacles to the migration of such animals as the 

 scallops. The occurrence of this deep gulley in the Firth places as great 

 a hindrance to the extension of the bed as does a high mountain range to 

 the distribution of birds, insects, and other animals. But these bathy- 

 metrical conditions do not obtain in the vicinity of Inchkeith. It is, there- 

 fore, here that the smaller northern and the large principal beds approach 

 each other. That they are not united together cannot be accounted for 

 by any deepening of the sea-floor. The suggestion that the smaller is an 

 offshoot from the larger bed is quite likely to be a true indication of the 

 origin of the former bed, as doubtless some individual scallops might be 

 able to accomplish the journey. But the question may be raised, if mi- 

 gration is possible, why are scallops not found on the area intervening 

 between the two beds % An odd example may be and has been dredged 

 from this interval, which shows that migration is perfectly possible, even 

 likely. That the beds are not continuous is doubtless due to the character 

 of the estuarine deposit covering the sea-floor. The mud there is in such 

 a fine state of division as to prevent the scallops living for any length of 

 time among it and differs very much from the material of the bottom upon 

 which scallops are usually found. So finely comminuted are the particles 

 of which the mud is made up that it resembles closely in character the till 



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