THE DALES OF DERBYSHIRE. 59 
did the limestone rock come from, and how did it assume 
its present arrangement? All the limestone rocks, forming 
part of the earth’s crust, wherever found, are largely com- 
posed of the remains of living organisms, foraminifera, 
corals, encrinites, molluscs, and shells of many kinds. In 
the old limestone rocks of Canada, we have the maps 
made up of the remains of that curious organism, Eozoon 
Canadense. Again, if we examine a portion of the lime- 
stone of which the Dales are composed, we find it consti- 
tuted of the debris of sbells of many kinds, encrinites, 
corals, etc. Other portions of the limestone are composed 
of the minute shells of foraminifera, etc., only distinguish- 
able when thin sections of the limestone are made and 
examined under the microscope. Some similar forms are 
secreting in limestone to-day. The hummulitic limestone 
of Egypt is composed of these beautiful remains. All 
limestone, in fact, is composed of the shells of the above 
and similar minute organisms, which secrete carbonate of 
lime to form their hard walls, or skeletons. From these 
facts, and from the increase of limestone rocks on the 
earth’s crust, the earlier geologists concluded that the 
living organisms generated the carbonate of lime, and, 
although there would be some difficulty for me to prove 
absolutely to you that this is erroneous, we need have no 
doubt that the organisms did not generate the calcium 
carbonate, but simply secreted it from the water in which 
we know it exists and existed, its original source being in 
the older rocks of the earth’s crust, in which large quantities 
of lime in combination with silica and alumina are found. 
These compounds, under the influence of heat and of water 
containing carbon dioxide, were broken down, the lime 
being retained in solution in the water by excess of carbon 
dioxide, and being carried away to lakes and seas, where 
it only awaited the advent of the carbonate of lime 
secreting organisms to recommence the formation of lime- 
