14 



BATHYMETRICAL SURVEY OF 



distance along the western side of the loch. The slope from the eastern 

 shore is, generally speaking, more gradual. The 25-feet depression is 

 divided into two portions by the rising of the floor of the loch about a 

 quarter of a mile from the southern end. The maximum depth in the 

 smaller southern depression is 49 feet. The larger 25-feet depression, 

 separated from the smaller one by an interval of about one-eighth of a 

 mile, is over 1J miles in length, approaching close to the north-western 

 end of the loch, with a maximum breadth of three-eighths of a mile. 

 This larger depression is very irregular in outline, occupying nearly the 

 full width of the loch towards the centre, while a short distance farther 

 south there is a narrow constriction in the vicinity of the Heron islands. 



FIG. 9. LOCH CHON. 



(Photograph by G. W. Wilson.) 



The area of the bottom between the shore line and the 25-feet 

 contour is about 119 acres, or 43 per cent, of the total area of the loch; 

 that between the 25- and 50-feet contours is about 127 acres, or 46 per 

 cent., and that deeper than 50 feet is about 32 acres, or 11 per cent. 



Lochan Dubh (see Plate VIII.). This little basin is one-fifth of a 

 mile in length, and less than one-sixth of a mile in maximum width. 

 Its waters cover an area of about 11 J acres, and it drains an area 

 eighteen times greater, or about 205 acres. The mean breadth is less 

 than one-tenth of a mile, or 45 per cent, of the length. Twenty-five 

 soundings were taken in Lochan Dubh, the maximum depth observed 

 being 41 feet. The cubic mass of water is estimated at 586,000 cubic 



