328 PROCEEDINGS OF SECTION C. 



in a short report which was afterwards published in the United States 

 "Economic Geology," Vol. I., pages 134-142. That is the first paper 

 ever published on the diamond regions of Bahia that gives any clear 

 idea of its geology. Professor Derby, however, did not have time to 

 do more than determine the horizon from which the diamonds came 

 in one part of the field, and to note that the diamond-bearing series 

 of sediments, which he called " the Lavras series," was underlain by 

 another barren one, which he called ''the Paraguassii series," and 

 that they were both somewhat folded. 



Though much remains to be done in order to give a full account 

 of the diamonds of Brazil, this brief outline may be of some service to 

 geologists in other parts of the world who may have occasion to 

 study the diamond question under conditions that appear at first to 

 be widely different from those under which they are found in Africa. 



It is hoped that it may be useful also in reminding intelligent 

 citizens that eveiy enlightened Government owes something to its 

 mining industries in the way of scientific study of the geology upon 

 which the success and existence of those industries depend. 



