520 



jVA TURE 



[September 20, 1906 



Buddhist scholar, might, no doubt, had he wished to 

 do so, have quoted a passage from some work held 

 in authority in Tibet giving the explanation required. 

 There is a charming report in one of the closing 

 chapters of an interview the author had with 

 Gahldan Cardinal, who had been appointed Regent 

 bv the Dalai Lama on the eve of his flight. He is 

 described as a man of striking presence, as one of 

 the most learned and profound scholars in Tibet, and 

 at the same time as a man of strong character and 

 skilled in affairs. There are evidently some Lamas 

 who read their books : and though their views and 

 ours may be altogether different, there can be little 

 doubt but that we also, if they were only made 

 accessible by good translations, should find in them 

 valuable materials for the history of that Eastern 

 culture which it is day by day becoming more and 

 more important for us to understand. We are 

 gratified to hear that the able 

 writer of this delightful book is 

 intending to devote the whole of 

 his time in future to these 

 studies ; and we trust that he will 

 succeed in unravelling for us some 

 more, and deeper, mysteries of 

 Lhasa. 



gradually developed a conception lying somewhere 

 between the theories of Sandberger and Posepny, 

 with a distinct leaning towards the teachings of the 

 latter. The mode of formation of mineral veins is, 

 however, still very far indeed from being understood. 

 The facts recorded by Prof. Park appear to show that 

 the majority of ore deposits are genetically connected 

 with igneous intrusions which may be plutonic or 

 volcanic. Circulating underground waters and gases 

 are the principal agents concerned in the dissolution, 

 primary concentration, and deposition of vein matter. 

 Ore deposits do not necessarily occupy pre-existing 

 fissures and cavities. Vein-filling was in many cases 

 effected by metasomatic replacement. Vein-filling 

 waters are ascending waters, but not necessarily deep- 

 seated. The mineral contents are derived from roclis 

 contiguous to the zone of fracture or zone of meta- 

 morphism. The accessory agents of dissolution are 



MINING GEOLOGY.' 

 '"PHE literature of economic 



^ geology is by no means in- 

 considerable, for since the publi- 

 cation in 1SS4 of John Arthur 

 Phillips's classic work on ore de- 

 posits, much attention has been 

 devoted to the study of mineral 

 deposits, and in the United States, 

 in particular, theories of the form- 

 ation of such deposits have been 

 propounded with bewildering fre- 

 quency. Prof. Park's text-book 

 under notice, which covers tlie 

 ground that is gone over in the 

 elementary course in the subject 

 at the LIniversity of Dunedin, New 

 Zealand, will, therefore, un- 

 doubtedly prove useful to the 

 mining student. 



The author deals with the sub- 

 ject in nine chapters. The first 

 contains a brief summary of geo- 

 logical principles, and tlie follow- 

 ing chapters are devoted re- 

 spectively to the classification of 

 mineral deposits, ore veins, the 

 dynamics of lodes and beds, ore 

 deposits considered genetically, the theories of vein 

 formation, ores and minerals considered economically, 

 mine sampling, and the examination and valuation 

 of mines. The chapter dealing with the genesis of 

 ore deposits is of special interest. The perplexing 

 problems by which the subject is surrounded are 

 judicially dealt with. The fascinating theory of lateral 

 secretion to which great support was given by Sand- 

 berger's brilliant researches, although strongly opposed 

 by Prof. Stelzner, of Freiberg, and by Prof. "Posepny, 

 of Przlbram, found much support in Am£rica in a 

 more or less modified form. Posepny's ascension hypo- 

 thesis has not been endorsed by succeeding investi- 

 gators in its integrity, and American geologists have 



} "A Text-book of Mining Geology." By James Park. Pp ix+219, 

 with 78 illustrations and 3 plates. (London : Charles Griffin and Co., Ltd., 

 3906.) Price 6s. 



NO. 1925, VOL. 74] 



heat and pressure, aided by dissolved alkaline minerals. 

 Precipitation from the ascending waters takes place 

 in more or less orderly horizontal zones in accordance 

 with the laws governing solution and precipitation. 

 Lastly, secondary enrichment is, in the majority of 

 cases, due to the migration of mineral contents from 

 a higher to a lower level, through the agency of 

 descending waters. 



Some interesting observations on the action of 

 ascending alkaline waters in New Zealand are recorded 

 by the author. Around Lake Rotorua ore deposits of 

 the solfataric class can be seen still in process of 

 formation on a scale of considerable magnitude. At 

 the hot springs the sinter encrusting the walls of the 

 fissures and pipes from which the waters escape at 

 the surface is hard and chalcedonic, and arranged in 

 laj'ers which often present a fine, ribbon-like structure. 



