732 report— 1884. 



rest, therefore, on more substantial bases of facts than could have been suspected 

 by any one unacquainted with these customs. 



This method of combining the results of geological research with historical 

 records the author has found on previous occasions to have the advantage of bring- 

 ing the geologist into touch with the rest of humanity, attracting as it does the 

 interest of historians, linguists, and others, who find in the facte so presented to 

 them pabulum applicable to the requirements of their own particular pursuits. 



In this paper it will not be necessary or suitable to enter at length into details 

 — the author having done so elsewhere. 1 His object is rather to direct attention 

 to the subject generally, and to make known the fact that much has been accom- 

 plished of late years, which has not as yet found its way into manuals and ency- 

 clopaedias. Most of the information to he found in such works is far behind our 

 present knowledge ; and, where not actually incorrect, has been superseded by 

 fuller and more accurate observations. The subjects taken for special consideration 

 are the following : — Diamond, ruby, sapphire, spinel, beryl, emerald, lapis-lazuli, gold, 

 silver. The steel of India, or wootz, might be included here, since at least 2,000 

 years ago it was one of the most precious productions of India. 



11. What is a Mineral Vein or Lode ? By C. Le Neve Foster, B.A., 



D.Sc, F.G.S. 



The author quoted briefly the definitions of a mineral vein given by Werner, 

 Carne, B. von Cotta, Grimm, A. von Groddeck, Geikie, Sandberger, and Serlo, who, 

 in common with most geologists, have looked upon mineral veins as ' the contents 

 of fissures.' While admitting that a very large number of veins may be so described, 

 the author contended that the exceptions are sufficiently important and numerous 

 to warrant a change in the definition. He is of opinion that many of the principal 

 and most productive tin-lodes in Cornwall are simply tabular masses of altered 

 granite adjacent to fissures ; and he brought forward the opinions of other geologists 

 to show that certain veins in the English Lake district, the Tyrol, Nova Scotia, 

 Nevada, Colorado, California, and Australia are not filled-up fissures. In conclusion, 

 he proposed the following definition : ' A mineral vein or lode is a tabular mineral 

 mass formed, more or less entirely, subsequently to the enclosing rocks.' 



TUESDAY, SEPTEMBER 2. 



The following Papers and Reports were read : — 



1. Plan for the Subject-Bibliograjjliy of North American Geology. 



By G. K. Gilbert. 



The United States Geological Survey is engaged on a Bibliography of North 

 American Geology. The work when completed will give the title of each paper, 

 with the title-page of the containing book, and the number of plates, the whole 

 being arranged alphabetically by authors. 



There is in contemplation also the simultaneous preparation of a number of 

 more restricted bibliographies, each covering a division of geologic literature. The 

 plan includes abbreviated titles of papers, with reference to the pages on which the 

 special subjects are treated, the entries in each bibliography being arranged alpha- 

 betically by authors. 



The selection of topics for treatment in this manner involves the classification 

 of geologic science, and the author submitted a tentative classification, requesting 

 the criticisms of geologists. 



1 ' Economic Geology of India,' and ' A Geologist's Contribution to the History of 

 India,' Proc. Roy. Rub. Soc. 1883. 



