co:n'tejN'ts 



CHAPTER IX 



ANCIENT GLACIAL ErOCHS, AND MILD CLIMATES IN THE AECTIC 

 EEGIONS 



Mr. Croll's Views on Ancient Glacial Epochs — Effects of Denudation in 

 Destroying the Evidence of Remote Glacial Ei)ochs — Rise of Sea-level 

 Connected with Glacial Epochs a Cause of Further Denudation — What 

 Evidence of Early Glacial Epochs may be Expected — Evidences of Ice- 

 action During the Tertiary Period — The Weight of the Negative 

 Evidence — Temperate Climates in the Arctic Regions — The ]\Iiocene 

 Arctic Flora — Mild Arctic Climates of the Cretaceous Period — Strati- 

 graphical Evidence of Long-continued Mild Arctic Conditions — The 

 Causes of Mild Arctic Climates — Geographical Conditions Favouring 

 Mild Northern Climates in Tertiary Times — The Indian Ocean as a 

 Source of Heat in Tertiary Times — Condition of North America During 

 the Tertiary Period — Effect of High Excentricity on Warm Polar 

 Climates — Evidences as to Climate in the Secondary and Paleozoic 

 Epochs — AVarm Arctic Climates in Early Secondary and Palaeozoic Times 

 — Conclusions as to the Climates of Secondary and Tertiary Periods — 

 General View of Geological Climates as Dependent on the Physical 

 Features of the Earth's'Surface — Estimate of the Comparative Effects 

 of Geographical and Phvsical Causes in Producing Changes of Climate. 



Pages 169—209 



CHAPTER X 



THE earth's AGE, AND THE RATE OF DEVELOPMENT OF ANIMALS AND 



PLANTS 



Various Estimates of Geological Time — Denudation and Deposition of 

 Strata as a Measure of Time — How to Estimate the Thickness of the 

 Sedimentary Rocks — How to Estimate the Average Rate of Deposition 

 of the Sedimentary Rocks — The Rate of Geological Change Probably 

 Greater in very Remote Times — Value of the Preceding Estimate of 

 Geological Time — Organic Modification Dependent on Change of 

 Conditions — Geographical Mutations as a ]\Iotive Power in Bringing 

 about Organic Changes — Cliniatal Revolutions as an Agent in Produc- 

 ing Organic Changes — Present Condition of the Earth One of Excep- 

 tional Stability as Regards Climate — Date of Last Glacial Epoch and 

 its Bearing on the Measurement of Geological Time — Concluding 

 Remarks Pages 210—240 



