INTRODUCTION. 75 



horizons of the crust and under very great pressure, and the 

 occurrence of granite as dykes in various British localities. 

 His treatment of valley and lake erosion is extremely able. 

 And Playfair was the first geologist who realised that the huge 

 erratic blocks might have been carried to their present position by 

 former glaciers. His insight in this respect would alone have 

 won for him a lasting fame, for the erratics on Alpine slopes 

 and plains had long been observed by geologists and an 

 explanation vainly sought. Playfair also studied the raised 

 beaches on the coast-line of Scotland, and rightly concluded 

 that they afforded evidence of an actual uprise of the land, in 

 opposition to the views of Linnaeus and Celsius, who had 

 explained a similar series of phenomena in Sweden as a result 

 of the retreat of the ocean. Playfair gave the first complete 

 account of the evidences of oscillations of level in European 

 lands. 



Playfair's style is a model of clearness and precision, and 

 his arguments are always thoroughly logical, and in agreement 

 with physical laws. His Huttonian Theory was translated into 

 French by C. A. Basset in 1815. 



Theories of the Earth's Origin proposed by De Luc, De la 

 Melherie, Breislah, Kant, Laplace, and others. Although 

 Hutton had enunciated his theory of the earth without 

 introducing any personal element, it was a foregone conclusion 

 that a doctrine which undermined the whole foundation of 

 Werner's Neptunian teaching, was bound to meet with adverse 

 criticism. Mention has already been made of the attacks 

 made by Kirwan, Professor of Mineralogy in Dublin (Geo- 

 logical Essays, 1799). His arguments are based upon 

 chemical and physical objections to Hutton's theory, and 

 culminate in a bitter denunciation of a theory inimical to 

 religion, and at variance with the Mosaic account, inasmuch 

 as it demanded immeasurable epochs in place of the Biblical 

 chronology, and even denied the universal deluge, to which 

 Kirwan mainly ascribed the present configuration of the earth. 



Another antagonist of Hutton's theory was the versatile 

 Jean Andre de Luc, a Genevese by birth, who came into 

 public notice during the political struggles in Geneva in the 

 middle of the last century, and afterwards attained to a 

 favoured position in the court of Queen Charlotte of England. 

 De Luc wrote on all manner of scientific subjects, and his 



