xvi CONTENTS 



THE WORK OF AN ICE-SHEET 864 



Formations made by the ice-sheets, 864. Fluvio-glacial deposits, 

 869. Relations of stratified to unstratified drift, 872. Topo- 

 graphic distribution of stratified drift, 872. Changes in drain- 

 age effected by glaciation, 873. The succession of ice invasions, 

 874. The loess, 885. Duration of the glacial period, 890. 



THE CAUSE OF THE GLACIAL PERIOD 894 



Hypsometric hypotheses, 895. Astronomic hypotheses, 895. 

 Atmospheric hypotheses, 898. 



FORMATIONS OUTSIDE THE ICE-SHEETS 899 



On the Atlantic and Gulf coasts, 900. In the interior, 904. In 

 the West, 905. Igneous rocks, 911. 



CHANGES OF LEVEL DURING THE PLEISTOCENE 911 



LIFE OF THE PLEISTOCENE 914 



Destructive effects of glaciation, 914. To-and-fro migration, 914. 

 Climatic adaptations, 915. Land life of the interglacial stages 

 in glaciated areas, 916. Marine life, 917. The terrestrial life of 

 the non-glaciated regions, 918. Pleistocene life outside .North 

 America, 920. Man in the glacial period, 922. 



CHAPTER XXXI 



THE HUMAN OR PRESENT PERIOD 



THE PRESENT PERIOD COMPARED WITH THE PLEISTOCENE 931 



The end of the glacial period, 931. The end of the deformation 

 period, 931. The channels on the continental borders, 933. 



LIFE OF THE HUMAN PERIOD 935 



The re-peopling of the glaciated areas, 935. The dynasty of man, 

 937. Man as a geological agency, 941. Prognostic geology, 942. 



REFERENCE TABLE OF THE PRINCIPAL GROUPS OF PLANTS 944 



REFERENCE TABLE OF THE PRINCIPAL GROUPS OF ANIMALS 945 



