C— GEOLOGY. 51 



lowland peat-bog coextensive with, not merely the coal-seam as it 

 now exists, but with its much greater development before denudation 

 had clipped its edges or cut it into several detached areas. This must 

 be our starting-point and principal postulate. 



In obedience to the wholesome admonition that the geologist should 

 interpret the past by the present, I have sought in descriptions of the 

 great alluvial areas of the world for some tract that shall exhibit to us 

 conditions closely paralleling — after allowance for biological differences 

 — those of Coal Measure times, especially as regards the extent of the 

 areas of peat formation. In the great Dismal Swamp of Virginia some 

 resemblance may be found, but the area is far too small. The Amazon 

 alluvium is comparable in area, but we have no knowledge of the peats. 

 The deltas of the Nile and the Indus equally fail us. The Ganges 

 delta comes much nearer. But after long flights of inquiry in many 

 parts of the earth I find that one of the best illustrations lies very 

 literally at our doors. At some period subsequent to the Pleistocene 

 Ice Age the whole of the British Isles appears to have stood — relatively 

 to the sea — at the least 80 ft. above its present level, and this uplifted 

 position similarly affected Holland, Belgium, and much of France. 

 The North Sea, in its southern half, appears to have been brought 

 by the net effect of glacial erosion and deposition to the condition of a 

 vast plain so nearly at the then sea-level that it became a morass. 

 Round its margins were forests of oak, pine, and birch, while the greater 

 part of the area furnished the conditions for a great peat-swamp. 

 Under favourable conditions of tide, peat-beds, with or without the 

 frayed and torn stumps of trees in position of growth, may be seen 

 below high-water mark, and in this city of Hull the Forest Beds 

 are exposed when deep cuttings are made or they are encountered in 

 borings. In Holland the peat-beds are similarly present, and in the 

 excavations for docks at Antwerp a peat-bed was found, overlain by a 

 deposit with estuarine shells. This evidence alone would do no more 

 than prove a fringe of swamps surrounding the North Sea, but the 

 trawlers who rake every square mile of the North Sea floor find their 

 operations impeded in places by masses of peat (Moorlog). Clement 

 Eeid, to whom we owe much of our knowledge of Post-glacial con- 

 ditions, expressed his interpretation of the physiography of the North 

 Sea area at this stage in a map which showed the portion of the North 

 Sea south of a line joining Flamborough Head to the northern point 

 of Denmark as a plain intersected by the multiple tributaries and mouths 

 of the Ehine, the Weser, the Elbe, and other rivers, 



If we assume that the peat-beds found on the margins and at many 

 stations upon this sea-floor were once approximately continuous, the 

 area would furnish the nearest modern parallel in respect of size to the 

 ancient peat-morasses which the coalfields must once have presented. 

 Beyond this the parallelism fails us. The Coal Measures of England 

 !vre preponderantly of fresh-water origin, as the recurrent beds of 

 Carhonicola and its allies demonstrate, while the Holocene peats of 

 the Dogger Bank and Holland are associated chiefly with marine or 

 estuarine deposits. The coals of the Lower Carboniferous of the North 

 of England and of the Scottisli Lowlands, on the other hand, present 



