656 E. 31. Kindle — Limestone Solution. 



which the water pressure is equivalent to about six atmospheres. 

 The temperature at this level is also always low ; both pressure 

 and temperature factors thus combine to give the water at that 

 depth a potential capacity for holding at least six times its 

 volume of carbon dioxide or about six times the amount which 

 it is capable of holding at the surface. The amount of the 

 gas actually dissolved in the water at that depth would be also 

 conditioned by the nature of the source of supply. If any large 

 or important source of carbon dioxide supply exists at the 

 bottom at 150' and greater depths, it is very evident that the 

 water there, owing to its multiplied capacity for absorbing the 

 gas, will hold much greater quantities of it than near the surface 

 and act as a solvent of limestone with correspondingly greater 

 effectiveness. Living animals and plants are the great sources 

 of carbon dioxide in lakes as well as in the sea. " Where life 

 is abundant, there carbon dioxide is abundant also and its 

 activity as a solvent of calcium carbonate is greatest."* The 

 discovery which has been described on a preceding page of an 

 abundance of green algge in these deep waters demonstrates the 

 presence of a very important source of this gas in the algal 

 flora of the lake bottom. Another though less important 

 source of the carbon dioxide is represented by the fresh water 

 sponges and molluscan fauna found in the same habitat. The 

 abundance of fish which makes the area under consideration a 

 favorite fishing ground of the Brighton deep water fishermen 

 affords collateral evidence of a wealth of bottom life which 

 makes it a good feeding ground for fish. The evident abun- 

 dance of animal" and algal life must afford a rich and constant 

 supply of carbon dioxide to these bottom waters of the lake. 

 The metabolism of the algse which grow directly on and often 

 completely cover the limestone slabs which have been brought 

 up must furnish a continuous supply of carbon dioxide to the 

 lowest zone of the lake. Water at this depth would seldom 

 be disturbed by wave action and except when affected 

 by occasional bottom currents would generally remain motion- 

 less. It would thus appear that under ordinary conditions the 

 metabolism of the plant life and molluscan life on the bottom 

 would result in a bottom zone of lake water becoming very 

 highly charged with carbon dioxide. The lake water would 

 therefore act as a much more effective solvent at the bottom 

 than near the surface and to this fact chiefly is due, the writer 

 believes, the deep and rapid corrosion of the limestone. 



Victoria Memorial Museum 



Geological Survey, Ottawa, Canada. 



* W. L. Carpenter and C. Wyville Thompson, Depths of the Sea, 1874, pp. 

 502-511. 



