Mr. Godwin- AitsteTL 8 Address. 473 



is a region which presents broad expanses of watcrworn detritus, 

 sands, and loams, often placed at considerable elevations above pre- 

 sent water-levels, which, from their superficial extent, has caused 

 them to be identified with the component members of another de- 

 trital group (the Glacial Drift) peculiar to another area, from which 

 they are distinct as to conditions and mode of accumulation. The 

 conditions indicated are those of low winter temperatures, terrestrial 

 surfaces with a configuration such as the same countries have at 

 present, alluvial and fluviatile accumulations, indicative of tor- 

 rential and periodic rivers. 



A line drawn across the European area, occasionally on one side or 

 other of that of north lat. 51 deg., defines the north limit of all this 

 class of detrital accumulations of the Kainozoic period ; on the south 

 of this all these accumulations have their limits, and the sources of 

 their materials are within the areas to which belong the existing 

 river-systems of the South and Mid-European continent. 



North of this line the detrital accumulations are neither local as to 

 composition, nor have they much reference to surface configuration, 

 although such configuration pre-existed. Over this area, too, are the 

 indications of low temperatures and broad alluvia. The distribution 

 of the detritus over this area shows that the expanse of water was 

 continuous, and was marine. Over one area are the results of a 

 general and uniform submergence ; over the other the phenomena 

 are local and alluvial. 



Over the British and part of the European area there is a good 

 break in Kainozoic time into Prseglacial and Postglacial ; by the 

 term "Glacial " being signified the period of the great extension of 

 the Arctic basin. 



This Drift-formation, in one form or another, covers the whole 

 surface of this county, from the sea-level up to the summits of the 

 Chalk hills. We have, in Norfolk, evidence of submergence to the 

 extent of 600 feet and upwards. There are other parts of this island 

 where the submergence exceeded this, even in this latitude ; so that 

 here the highest land may not be a measure of the greatest amount 

 of submergence. It was a time when the whole of the British- 

 Islands group became submerged, with the exception of a few salient 

 points ; and, taking the levels to be derived from these points, to- 

 gether with the general character of the phenomena, we may accept as 

 certain that subaerial glaciation, in all its varied modes of action, 

 had long been at work here prior to that submergence. The change 

 of relative level was not sudden ; it proceeded from north south- 

 wards ; and it is in the north that the amount of the submergence 

 was the greatest. 



Tlie Drift of Norfolk has good illustrations of these several sets of 

 conditions, and of the manner in which the phenomena of one period 

 have been modified by conditions which followed. It has been well 

 said that in geological history time is of no object ; but in a geological 

 address, such as this, it has its claims ; so that instead of dwelling 

 at any length on the general condition of the British Islands at the 

 time of their greatest submergence, I have represented on a map of 



VOL. V. — NO. LIT. 31 



