President's Address. 21 



in the boulder clay clearly show that the ice must have 

 marched inland from the bed of the adjoining firth. In like 

 manner, the ice which moved seawards from Strathmore was 

 deflected towards the north after reaching the present coast- 

 line, bearing along with it the moraine profonde derived from 

 the Old Ked Sandstone area. And so, also, the great wer de 

 glace that streamed from the Great G-len into the basin of the 

 Moray Firth must have crossed the north-eastern part of 

 Aberdeenshire ; while a portion of the same ice-sheet must 

 have been deflected towards the north-west so as to over-ride 

 a portion of Caithness. For our present purpose, it is of 

 little moment whether these changes in the trend of the ice- 

 flow in the Moray Firth w^ere due to the fanning of the great 

 glaciers, or to the presence of Scandinavian ice in the North 

 Sea. It is enough to indicate that the direction of the ice- 

 markings, the distribution of the stones in the boulder clay, 

 and the organic remains, point to the conclusion that the 

 Highland ice ploughed up the accumulated sediments in the 

 basin of the Moray Firth, and deposited them over part of 

 Caithness and the Orkney Islands, in the form of a dark, 

 shelly boulder-clay. The assemblage of fossils in the Caith- 

 ness and Orcadian boulder-clay is rather remarkable. Most 

 of the shells are not of an Arctic type, but belong to species 

 still living round our shores. Along with these, however, 

 some extinct forms are associated. No less interesting is the 

 occurrence of recent species of foraminifera in conjunction 

 with species which must have been washed out of the chalk. 

 The chalk foraminifera, like the chalk flints, were most pro- 

 bably derived from the pre-glacial denudation of Cretaceous 

 beds which once fringed the Moray Firth basin. Almost all 

 the shells in the Caithness boulder-clay which could retain 

 traces of glaciation are smoothed and striated like the stones 

 in this deposit. None is found in the places where they 

 lived and died. It is a significant fact that few remains of 

 shore shells have been met with, most of the shells being of 

 the same species as those now inhabiting the sub-littoral 

 zone of our islands. To some it has been a source of wonder 

 that the shells of the Caithness boulder- clay are not of the 

 same Arctic type as those derived from the glacial clays of 



