nil 



PROCEEDINGS 



OF THE 



AMERICAN PHILOSOPHICAL SOCIETY 



HELD AT PHILADELPHIA 

 FOR PROMOTING USEFUL KNOWLEDGE 



Vol. L January-April, 1911 No. 198 



THE FORAL\TIOX OF COAL BEDS. 



I. 



An Historical Summary of Opinion from 1700 to the present 



TIME. 



Bv JOHN J. STEVENSON. 

 (Read April Ji, 191 1.) 

 Preliminary Note. 



Preparation of a monograph on any subject which interests stu- 

 dents in many lands requires thorough study of the hterature as a 

 preparatory step. But that Hterature has grown to such proportions 

 tl It one often becomes discouraged and is burdened with the fear 

 tha' hfe will be spent in making ready and that the grave \\'\\\ have 

 been reached before the monograph has been begun. Yet such pre- 

 liminary research is not without compensation, for one discovers that 

 his own period is not so far in advance of days gone by as he had 

 supposed ; that his contemporaries, with all their advantages, have 

 done little more, in many instances, than to place newer and finer 

 clothing on the generalizations of earlier students who had vvorked 

 within narrower areas. 



This is not to say that niodern workers have appropriated know- 

 ingly the results obtained by iheir predecessors. The writer has dis- 

 covered very few instances of ^hat sort. For the most part, generali- 

 zations have been made, dc noyo, in ignorance of those previously 

 formulated. The literature has become vast; the papers are scat- 



PROC. AMER. PHIL. SOC. L. I98A, PRINl.'.D APRIL 24, I9II. 



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