PREFACE. 



FBO:.I the days when Geology began to develop into an exact 

 science, the student has been encountered by guides in the form 

 of books, of two kinds ; one promising to " lead him the sweetest 

 and easiest way ; " the other demonstrating that " of things good 

 and beautiful, the Gods give nothing to men without great toil." 

 The earlier writers gathered facts from too wide a field to 

 demonstrate the steps of geological evolution. In the words of 

 Professor Suess : " It is an exceedingly difficult task to teach a 

 science well, which grows as rapidly as ours. The difficulty is 

 not caused by the enormous yearly increase of new observations, 

 because this may be overcome by patience, and by a diligent 

 study of every good memoir. But I find that many of our best 

 men go wrong in hanging to details, and losing sight of the 

 grand features of science, or in proclaiming popular theories, 

 and forgetting the painful arts of observation amidst the 

 applause of a short-sighted crowd." l The difficulty of teaching 

 has also been the difficulty of text-book writing. And among 

 the few works which have aspired to achieve a noble ideal, 

 probably the most honoured place must be given to the Manual 

 of Professor John Phillips. As the nephew of William Smith, 

 he knew the history and growth of geological ideas as well as 

 facts ; and as a public teacher was not unmindful of the aspects of 

 geology which are of vital importance in unfolding thought and 

 imagination for the learner. He was thus eminently fitted to 

 state the principles of the science in their mutual dependence ; 



1 Letter of 1866. 



