Editorial Comment 265 
being divided into two while the other between • England and 
Ireland is larger but in the same region. The northwest of 
Scotland and of Ireland is part of a great continental mass 
whose farther limits are unrepresented and all the British area 
and the adjoining continent are lying under the waters of the 
early Silurian sea. 
The transition to the Lower Devonian geography is almost 
kaleidoscopic. Every thing is changed. Sea occupies the 
south of Ireland and the south of England while the area to 
the north is dry. But the Scottish district shows five lakes, 
two of them rivaling in size those of North America. Lake 
Caledonia covers the sites of Edinburgh and Glasgow and 
stretches to the northeast into the sea and to the southwest as 
far as Ireland and resembles lake Michigan in form and size. 
Lake Orcadie lies on the site of the Orkneys and the north- 
east of Scotland stretching far over the sea towards Norway. 
This restoration is in accordance with the view that while the 
limestones of Devon and Belgium are undoubtedly of marine 
origin the Old Red Sandstone was most likely laid down in 
the bottoms of lakes. Evidence of this is afforded by its fos- 
sils which are for the most part plant-remains and ganoid fish. 
It is not improbable that when the Devonian geography of 
North America is restored similar conditions will be found to 
have prevailed on this side of the Atlantic. The Red Sand- 
stone of the Catskill group gives evidence of a similar origin 
and was probabl}^ deposited in a great lake covering part of 
New York and Pennsylvania. 
In the Lower Carboniferous era the map represents a large 
island in central England as in some preceding ages. This is- 
land lies in an arm of the sea covering nearly all of the British 
Isles except the northern part of Scotland which is shown as a 
portion of a great northern continent whose farther limits are 
unknown. Northwestern France also is part of another or per- 
haps of the same continental mass. 
The Carboniferous era in Britain seems as in this country to 
have been for the most part a time of repose. The land con- 
sisted of vast and swampy fiats on which grew the vegetation 
of the Coal-Measures and some explanation of the existence of 
the identical species on both sides of the Atlantic maybe found 
in the following statement : "At this period a large continent 
occupied the whole area of the North Atlantic and extended 
