444 Proceedings of Royal Society of Edinburgh. [sessJ 
with large steins, leaves, etc. ; it was only at about 500 feet that I 
found the deposits to be as finely pulverised as at about 50 feet in 
the Danish lakes. This phenomenon is easily accounted for — in 
our lakes everything in the shallow water between the shore and 
the 30-feet contour is pulverised by the dash of the waves, 
whereas in the Scottish lakes, owing to the precipitous hillsides, 
everything is carried away from shore by the rivers and waves, 
and subsides in depths of 200 to 300 feet, without being exposed 
to the eroding force of the waves on a shallow coast. 
From all the bottom-samples I have seen it appears that the 
deposition of organic matter is not nearly so abundant as in the 
Danish lakes, the deposits consisting principally of inorganic 
materials ; there is further a total absence of lime — a very con- 
spicuous difference between the lake-bottoms in the two countries. 
Further observations may show in wdiat manner the bottom fauna 
deals with the deposited material, and the changes to which this 
material is, in consequence, subjected ; 1 cannot but think that 
here also layers of “gytje” are being formed. 
I suppose that most of the observations on the influence of 
organic life upon the general conditions of the lakes and their 
surroundings in our own country will hold good also with regard 
to most of the lakes in the southern part of Sweden and in the 
northern part of Germany ; my investigations of the Danish lake- 
gytjes are in accordance with v. Post’s explorations of Swedish 
gytjes, and most of my observations with regard to the lime- 
deposits have been corroborated by Passarge. The explorations 
of Halbfass among the lakes of Pomerania show that the natural 
conditions of those lakes are very similar to those of our own. 
My Visit to the Lowland Lakes. 
Subsequent to my examination of the Highland lakes, I visited 
some lakes in the Lowlands, as well as some smaller lakes near 
Edinburgh, including Loch Leven — famous for its excellent trout. 
These lakes presented many points of similarity with those of our 
own country. I found in Loch Leven the same gently sloping 
shores, a very slight transparency of the water, and a considerable 
amount of detritus ; the mud was very fine, and the large amount 
