20 Proceedings of the Royal PJiysical Society. 



by the recent discovery of the skull of a Dicynodon in these 

 sandstones, now in the possession of my colleague, Mr Linn, 

 which was briefly described by our distinguished naturalist, 

 Dr Traquair, at the Aberdeen meeting of the British Associa- 

 tion. These reptilian remains have hitherto been obtained 

 only from Triassic strata in other regions. It would, indeed, 

 be rather remarkable if such highly-specialised animals as 

 those whose remains are found in the Elgin sandstones should 

 have continued without any modification from Old Eed 

 Sandstone to Triassic times. The discovery of reptilian 

 remains in Old Eed or Silurian rocks would not be in the 

 least astonishing, but we should expect them to possess 

 Labyriuthodont characters, or belong to a more archaic type. 

 The organic remains associated with the deposits of the 

 Ice age help to throw light on some of the phases of that 

 remarkable period. From evidence obtained over the greater 

 part of Scotland, it is apparent that the boulder clay is a 

 product of land ice. That such a formation should be almost 

 barren of fossils is just what might be expected when we 

 remember that the country must have been enveloped in ice, 

 which radiated from a few centres, and invaded the surround- 

 ing shallow seas. The organisms that flourished on the old land 

 surface previous to the advent of the glacial period have been 

 almost entirely removed ; and it is only at rare intervals that 

 a bone or tusk of the mammoth or other relic of terrestrial 

 life is unearthed from the till. The appearances presented 

 by these relics prove beyond doubt that they have been sub- 

 jected to the same abrasion as the stones in the boulder clay. 

 In some instances the ice, after invading arms of the sea, was 

 compelled to override tracts which now form land. Where 

 such was the case, we generally find that fragments of marine 

 shells are incorporated with the boulder clay, and possess 

 smoothed and striated surfaces, characteristic of glacial 

 action. Between Loch Lomond and the Firth of Clyde 

 there is undoubted evidence to prove that the shelly boulder 

 clay must have been pushed out of the bed of the loch on to 

 the adjoining land. Similar evidence is also met with along 

 the shores of Ayrshire and Wigtownshire, where the direction 

 of the ice-markings and the distribution of the stones 



