242 GLACIAL PERIOD IN SCOTLAND. chap. xiii. 



of the Scotch mountains was traced hy him to the height of 

 at least three thousand feet.* 



Professor Agassiz, after his tour in Scotland in 1840, an- 

 nounced the opinion that erratic blocks had been dispersed 

 from the Scottish mountains as from an independent centre, 

 and that the capping of ice had been of extraordinary 

 thickness. Mr. T. F. Jamieson, of Ellon, in Aberdeenshire, 

 has recently brought forward an additional body of facts in 

 support of this theory. According to him, the Grann^ians 

 were at the period of extreme cold enveloped " in one great 

 winding-sheet of snow and ice/' which reached everywhere 

 to the coast-line, the land being then more elevated than it 

 is now. He describes the glacial furrows sculptured on the 

 solid rocks as pointing in Aberdeenshire to the southeast, 

 those of the valley of the Forth at Edinburgh, from west to 

 east, and higher up the same valley at Stirling, from north- 

 west to southeast, as they should do if the ice had followed 

 the lines of what is now the principal drainage. The obser- 

 vations of Sir James Hall, Mr. Maclaren, Mr. Chambers^ and 

 Dr. Fleming, are cited by him in confirmation of this ar- 

 rangement of the glacial markings, while in Sutherland and 

 Ross-shire he shows that the Macial furrows alonf; the north 

 coast point northwards, and in Argyleshire westwards, always 

 in accordance with the direction of the principal glens and 

 fiords. 



Another argument is also adduced by him in proof of the 

 ice having exerted its mechanical force in a direction from 

 the higher and more inland country to the lower region and 

 sea-coast. Isolated hills and minor prominences of rock are 

 often polished and striated on the land side, while they remain 

 rough and jagged on the side fronting the sea. This may be 

 seen both on the east and west coast. Mention is also made 



* Ancient Sea Margins, Edinburgh, New Philosophical Journal, April, 

 1848. Glacial Phenomena, Edinburgh 185.', and January, 1855. 



