118 College of Forestry 
author calls attention to the fact that if this law was not in 
operation, many parts of the bottom would be devoid of both 
animal and vegetable life. 
An examination of the samples brought up by the bottom 
sampler, and by another instrument called the detritus 
sampler (inade of a cylindrical glass tube), showed that the 
iene was composed of two distinct layers ; the topmost being 
1-2 mill. thick, brown in color and of a fluffy appearance; 
and the second layer, which extends to the bottom of the 
sample, being of dark blue color, consisting of sand-mixed 
elay with organic remains. Bottom samples of this character 
are free from smell. Chemical examination of this top bot- 
tom deposit shows it to be composed largely of pectose, a 
substance present in Zostera, indicating clearly the origin of 
at least a part of the mater ial. The amount of carbon in the 
bottom material which is large in the areas near shore, 
diminishes progressively as the distance from shore increases, 
again indicating the influence of the plants in the formation 
of this rich bottom covering. Jensen also examined the 
water, by centrifuging, and obtained material identical with 
the top layer of the bottom deposits. The winds are there 
fore found to bear an active part in the distribution of this 
fine detritus material. 
The black, odoriferous layers found in certain parts of the 
region under consideration (and which were devoid of animal 
life) were found to contain a quantity of methane or marsh * 
gas, due to the presence of bacterial life, together with small 
amounts of oxygen and carbon oxide. Jensen describes the 
processes going on in this kind of a bottom as fermentative. 
The large percentage of hydrogen sulphide found in the inner 
fjords of Denmark and more largely in the Black Sea is due 
to the rich plant production, which is great enough to form 
a bottom-soil containing a large amount of organic matter. 
“Tn this way the possibility is created for a rich bacteria 
life, production of hydrogen sulphide and so on, which cer- 
tainly contribute to a very high degree to deprive the water 
of oxygen.” The sea furnishes the greater part of these 
fjords or bays with fresh oxygen, thereby preventing the for- 
