466 J. S. Gardner — Revision of the British Eocenes. 



when these were deposited it is difficult to see where the mass of ice 

 or land could have existed in Ireland to have exerted the requisite 

 attractive force. Again, we have shell-beds in Wales at 1350 feet, 

 but no trace of submergence in the valley of the Thames, only 200 

 miles off. It cannot be supposed that near London the sea stood 

 1200 feet lower than it did at Dublin, or 1350 feet lower than it did 

 in Wales. In the foregoing paper I have also given instances in 

 America and elsewhere which imply subsidence of land in the 

 interior of continents where no submergence beneath the sea 

 occurred, and where consequently changes of the sea-level do not 

 serve to explain the facts. 



Col. Clarke, in his recent treatise on Geodesy (1880, p. 96), says 

 that although mathematical calculation shows us that large tracts of 

 country may produce great disturbances of the sea-level, it is at least 

 questionable whether in point of fact they do. The attraction of 

 the Himalayas as deflecting the plumb-line at various places in 

 India has been computed, and it has been found that there is little 

 correspondence between theory and observation, for the attraction 

 of the Himalayas only makes itself perceptible to observation at 

 places quite close to them. 



An examination of the tables given by Mr. Buchan in the Trans- 

 actions of the Eoyal Society of Edinburgh, showing the mean height 

 of the barometer in various parts of the world, leads me to think that 

 the supposed influence of the continents and high masses of land in 

 drawing the ocean towards them, has been greatly overestimated by 

 the authors to whom Dr. Penck appeals. For these tables certainly 

 lend no countenance to the notion that the sea-level is subject to the 

 great inequalities of level which he assumes. 



VII.. — Suggestions for a kevised Classification op the Bkitish 



Eocenes. 

 By J. Starkie Gakdnee, F.G.S., etc. 



SINCE the British Eocenes, especially of the Hampshire Basin, 

 were mapped by the Survey, a portion of them have been 

 separated by several writers as Oligocene. The utility of the change 

 is not apparent in our country, where the break is seen to be purely 

 artificial; but in other parts of Europe the Oligocenes, which 

 embrace formations previously known as Lower Miocene, are of 

 great importance. This change, absorbing the entire Upper Eocene 

 fromation of the Isle of Wight, would seem alone to necessitate a 

 reconsideration of the classification of the remainder. But the classi- 

 fication of the Eocene formation, invented and often modified when 

 the beds composing it were imperfectly known, is throughout arbitrary 

 and artificial, and scarcely yet on a scientific basis. Most of the 

 present divisions comprise under one name the very distinct deposits 

 formed by river, sea, or estuary, though these have been brought 

 from quite opposite directions, and are perhaps by no means 

 contemporaneous. Some divisions, on the other hand, are so definitely 

 limited to sea-deposits of a particular quality, that other and con- 



