196 HUTTONIAN THEORY 



home. Thick sheets of snow are draped all over the 

 hills around, and far to the north-west the distant 

 gleam of glaciers and snow-fields marks the line of 

 the Highland mountains. As we muse on this strange 

 contrast to the living world of to-day, the scene ap- 

 pears to grow more Arctic in aspect, until every hill 

 is buried under one vast sheet of ice, 2,000 feet or 

 more in thickness, which fills up the whole midland 

 valley of Scotland and creeps slowly eastward into the 

 basin of the North Sea. Here the curtain drops upon 

 our moving pageant, for in the geological record of 

 this part of the country an enormous gap occurs 

 before the coming of the Ice- Age. 



When once more the spectacle resumes its move- 

 ment the scene is found to have utterly changed. The 

 familiar hills and valleys of the Lothian s have dis- 

 appeared. Dense jungles of a strange vegetation 

 tall reeds, club-mosses, and tree-ferns spread over 

 the steaming swamps that stretch for leagues in all 

 directions. Broad lagoons and open seas are dotted 

 with little volcanic cones which throw out their streams 

 of lava and showers of ashes. Beyond these, dimmer 

 in outline and older in date, we descry a wide lake 

 or inland sea, covering the whole midland valley and 

 marked with long lines of active volcanoes, some of 

 them several thousand feet in height. And still further 

 and fainter over the same region, we may catch a 

 glimpse of that still earlier expanse of sea which in 

 Silurian times overspread most of Britain. But be- 

 yond this scene our vision fails. We have reached 

 the limit across which no geological evidence exists to 

 lead the imagination into the primeval darkness beyond. 



