EDITOR'S INTRODUCTION 



A. J. Eardley's Structural Geology of North America has, since its pub- 

 lication in 1951, become something of a landmark in the geological litera- 

 ture of the New World. This is demonstrated by the broad base of its 

 foreign sales and the fact that, at home and abroad, the volume has re- 

 ceived heavy use by stratigraphers, geophysicists and other specialists, 

 as well as by the structural geologists for whom it was written. Moreover, 

 although originally conceived as a textbook for advanced undergraduates, 

 Structural Geology soon became a handy and valued general source book 

 for nonacademic professional and economic geologists. 



Dr. Eardley, however, has always considered that his magnum opus 

 was somewhat out of date even before the first edition was put through 

 the publishing mill. Accordingly, immediately after the book was issued, 

 he set about the onerous task of revising it. For a full decade now he has 

 devoted a considerable amount of his time and efforts to the current re- 

 vision. The self-imposed "labor of Hercules" has been particularly frus- 

 trating and time consuming because during the fifties numerous basic 

 concepts of structural geology have undergone radical change. Thus, 

 fondly held theories of less than ten years ago are now either discarded 



or seriously challenged. In addition, a vast quantity of new field data hai 

 been accumulating so rapidly that revisions can scarcely keep up with 

 the scientific progress. 



Dr. Eardley has taken full cognizance of the rapidK evolving theo- 

 retical concepts, as well as of the flood of new information. As a result 

 this edition of Structural Geology is far from being a reprint — in many 

 chapters it is so extensively revised as to be essentiall) a new volume. 

 But in addition, much of the best of the first edition reinainv .iud thus 

 it is likely that this volume will continue to be the standard text and 

 reference work in a subdiscipline of geologv that is of prime significance 

 in the proper understanding of all other phases of the subject 



The structural evolution of a continent! Relatively few scientific writers 

 have painted on such a broad canvas as Dr. Eardley. Hi' is something of 

 a rarity even among such artists, for he not only works with a broad 

 brush but also takes pains to fill in the details. 



The geological fraternity has been indebted to Dr. Eardley for an ex- 

 cellent compendium on structural geology, and that indebtedness is now- 

 increased through an exceptional initial task that has become even better 

 done in its redoing. 



( ' u.i ■> (. I iNl is 



Rice University 

 June, 1962 



XI 



