684 REPORT— 1887. 



least so far as the explored parts of this hemisphere are known, both the fauna and 

 flora at this epoch being co-extensive with the northern hemisphere, indeed in all 

 probability far wider, seeing that identical species occur in the Carboniferous series 

 of Australia and North America. Even those well-marked lines which at present 

 follow more or less closely the isotherms of our hemisphere seem not to have exercised 

 the same influence on the fauna and flora as they do at present. Thus in high northern 

 latitudes and within the arctic circle we find abundant evidence of life in Palaeozoic, 

 Mesozoic, and even down to Tertiary times, unaffected by latitude ; so that we are 

 justified in assuming that a far milder temperature extended to much higher 

 northern regions than that which at present exists on the globe, and consequently 

 that a larger portion of the earth's surface (as well as its seas) was then habitable. 



How great, then, is the field of research still open to our investigation, and how 

 far distant must that day be ere the last problem shall have been solved, and the 

 last chapter written, in the ancient life-history of our earth ! 



We write in sand, our labour grows, 

 And with the tide the work o'eriiows. 



With unskilled hand I have struck here and there only a few chords on the 

 many-toned harmonicon of geology. I fear they may not all have vibrated quite 

 in unison as a perfect composition would ; but, however crude the performance has 

 been, I trust that it will not be provocative of discord. If some few ideas suggest 

 themselves as worthy of your acceptance I shall not have spoken altogether idly, 

 nor you have listened so long and so patiently enthely in vain. 



The following Papers wei-e read : — 



1. Oji the Geography of tlie British Isles in the Garhoniferous Period. 

 By Professor W. Boyd Dawkins, F.B.S. 



In the Devonian age the great north-western continent, to which in 1886 I 

 gave the name of Archaia,' and which occupied the area of the North Atlantic in 

 the direction of Iceland, Greenland, and a large portion of North America, extended 

 southwards in Britain over the area of the British Isles as far as the line connecting 

 the Lower Thames with the Lower Severn. It was diversified by chains of mighty 

 lakes, embosomed in luxuriant forests of conifers, and various Lepidondendron and 

 ( 'alamitean trees. These lakes probably discharged their waters into the Devonian 

 Sea then covering the southern waters. At the close of this period the British 

 area sank beneath the waters of the sea until it was reduced to a cluster of islands 

 lying off" the coastline of Archaia, and each marked by the shingle-beaches. 



In dealing with the geography of the British Isles during the Carboniferous 

 period I propose to take the areas of Lancashire and Yorkshire as a starting-point, 

 and to divide the strata into two groups : — 



1. The Lower Carboniferous, consisting of — 



A, The Lower Carboniferous Shales, Sandstones, and Conglomerates. 



B, The Carboniferous Limestone. 



C, The Yoredale Series. 



2. The Upper Carboniferous, consisting of — 



D, The Millstone Grit. 



E, F, and G. The Coal-measures. 



The Lower Carboniferous Shales, Sandstones and Conglomerates, A of the 

 above list, rest for the most part unconformably on the older rocks: conformably, 

 however, on the Old Red Sandstone, and vary considerably in thickness, as might 

 be expected from their accumulation on a shore ranging from 4,000 feet in the 

 basin of the Clyde to about 100 feet in South Wales, and being represented under 



' Lectures before Koyal Institution. So called from the massif of the continent 

 being composed of rocks of Archaian age. 



