PREFACE. 



THIS glossary of the terms which have been used by geologists 

 in India has grown out of rough notes made from time to 

 time for my own private use when, as Director of the Geological 

 Survey, it was one of my duties to edit the departmental publi- 

 cations. Some of the terms naturally came into more frequent use 

 than others and for these the definitions were often reviewed and 

 repaired. As the definitioD in this way gradually became fixed, 

 the notes in turn proved to be of practical assistance in editing 

 the reports and memoirs prepared by junior officers, and thus arose 

 the idea of completing the glossary and of publishing it for the 

 general use of those within and without India who have now to 

 handle a literature that is becoming inconveniently extensive. 



In a few instances also the meanings of terms grew and some- 

 times became modified by personal discussion among the officers 

 of the Department, without formal publication of the circumstances. 

 In other cases terms were used at first in a tentative way when 

 there was insufficient ground for giving them a formal definition ; 

 these sometimes became fixed and recognised and at other times 

 became discarded, neglected or superseded. A beginner in Indian 

 geology would thus naturally find it difficult to trace the terms 

 to their origins, and might be puzzled by apparent inconsistencies 

 between the old and the modern literature. 



It was only after leaving the service that I found time suffi- 

 cient to undertake the necessary mechanical work of piecing to- 

 gether the notes, summarising the extracts from literature, of 

 checking the co-ordinates of the localities quoted, and of reducing 

 the entries to some approach to that uniformity which is neces- 

 sary to make a work of reference of practical value. 



I have taken advantage whenever possible of the advice and 

 help of many friends who have intimate knowledge of special 

 sections of Indian Geology ; to these, as they well know, I am 

 ever grateful. But I ought specially to mention the great assist- 

 ance that I have received from my colleague, Mr. G. H. Tipper, 

 whose unusually wide knowledge of the literature has enabled him 



