The Ancient Lakes of Edinburgh. 129 
its deposits, to the most typical lakes within the immediate 
range of our inquiry. The times represented by these lake 
silts or marls extend from the end of last century, as in the 
cases of the North Loch and the Borough Loch, back to the 
interglacial lakes of Hailes and Redhall. By the end of last 
century is simply meant that about that time the North 
Loch and the Borough Loch became extinct as lakes. As to 
the time when they first became lakes, Hugh Miller’s later 
suggestion in 1854—by which he amended his first suggestion 
in 1842 by extending their period from the time of the 
Noachian flood about 4000 years ago to the times of the later 
upheavals of the land, which in the case of the higher lying 
lakes might be four times 4000 years ago—must be taken as 
the nearest approach to the actual date we can at present 
make. The interglacial lakes of Hailes and Redhall must 
be considerably earlier in date than any of the others, which 
must all be reckoned postglacial; but to put it in figures is 
beyond our present intentions, 
THE Norru Locn. 
The material from this lake was given to us in 1871 by 
the late Mr J. Wallace Young, who obtained it from his 
uncle, Mr Bell, for many years chief engineer of the North 
British Railway. It was taken from the excavations for the 
new arrival platforms made at that time for the trains 
‘coming from the west. We cannot give any details of the 
thickness or extent of the deposit of which it was a part, but 
as it is said that the North Loch stretched from the Castle 
eastward to beyond the North Bridge, it was probably 
extensive, and most likely represented several diverse con- 
ditions determined by the depth and exposure of the water. 
The material from which the shells and Ostracoda were 
obtained was not marl as in most instances, but a brown 
earthy mud, which did not separate into dust or grains, but 
remained in small solid pellets even after boiling a consider- - 
able time. It is therefore evidently from the latest deposit 
ere the loch was drained dry, and the life remains are probably 
not more than 100 years old. When the railway was made 
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