Januarx- 31, 1908] 



SCIENCE 



189 



drilling is made particularly uncertain by a 

 large body of rock salt which takes part in an 

 over-thrust fault, the oil being found close to 

 the under side of the salt. The oil is usually 

 found under great pressure, and gushers are 

 quite common. The oil is usually black, 

 rather ethereal in its odor, and contains both 

 parafEne and asphalt. In many cases, by 

 natural diffusion the asphalt has been lost. 

 The oil is then light in color, and in specific 

 gravity. The oil carries a considerable pro- 

 portion of members of the benzol series, which, 

 of course, adds to the difficulty of refining. 



The scientific work of the congTess was 

 divided into three sections — the firet section 

 being devoted to geology and oil exploration. 

 Thirty-nine papers were presented in this sec- 

 tion, of which twelve were descriptions of 

 petroleum deposits, ten on theories of origin, 

 ten on methods of drilling, and the remainder 

 relating to oil-well management. H. Foster 

 Bain, Ralph Arnold and A. F. Lucas con- 

 tributed papers in regard to the Illinois, Santa 

 Maria, California and Texas fields, respect- 

 ively. Much attention was given to the dis- 

 cussion of structural details in the Rou- 

 manian fields. 



A most important result was pointing out 

 the evident importance of water in filling up 

 the pores of the rock which form covers to 

 the oil pools, and thus prevent the oil from 

 escaping. 



Mrazek's insistence on the function of 

 water in driving by capillary action the oils 

 from a diffused condition in shales, and com- 

 pressing them in relatively small sands, was 

 also of much importance for oil geology. 



In regard to theories of origin, Professor 

 Carl Engler replied to the criticisms which 

 have been made against his theory on the 

 animal origin of oil on account of the differ- 

 ence in optical activity between his oil pre- 

 pared from fish, and natural oils, by showing 

 that destructive distillation of cholesterine 

 gives products similarly optically active to 

 crude petroleum. 



The Association of Alunite with Gold at Gold- 

 field, Nevada: F. L. Ransome. 

 The alternation of the andesitic and rhyo- 



litic rocks of Goldfield which stands in closest 

 relation to ore deposition has resulted in the 

 removal of nearly all of their lime and 

 magnesia, three fourths of their soda and two 

 thirds of their potash. On the other hand 

 water and sulphuric acid have been added and 

 the iron of the original silicates has been con- 

 verted to pyrite. The introduction of sul- 

 phuric acid is shown in the extensive develop- 

 ment of alunite and some kaolinite and dia- 

 spore at the expense of the original feldspars. 



The solutions which deposited the ores were 

 acid and probably hot. They carried gold, 

 copper, bismuth, antimony, a little arsenic, 

 selenium and tellurium, hydrogen, sulphide, 

 and probably sulphurous and sulphuric acids. 

 Their solvent action on quartz was feeble. 



The recognition of alunite as a character- 

 istic constituent of the Goldfield ores and the 

 demonstration of its genetic relation to them 

 establishes a new type — that of alunitic and 

 kaolinitic gold-quartz veins, in the classifica- 

 tion of epigenetic deposits based upon the kind 

 of metasomatism effected in the wall rock by 

 the ore-depositing solutions. It is not be- 

 lieved that the Goldfield District is unique in 

 the possession of this type. Other examples 

 are likely to be found among the great num- 

 ber of ore deposits associated with Tertiary 

 voleanism. The constituents removed from 

 the Goldfield rocks are those which are de- 

 posited extensively in the production of gold- 

 quartz veins of the sericitic and calcific type. 

 Consequently conditions are conceivable under 

 which the acid solutions of Goldfield might 

 have ascended through a much thicker series 

 of rocks and given rise to sericitic and cal- 

 cific veins. 



Finally, the relation of the alunite and 

 kaolinite at Goldfield suggests the possibility 

 of the future discovery of metasomatic veins 

 of the pure alunitic type, without kaolinite. 



The Place of the Great Raised Beaches in 



Geology: H. W. Pearson. 



Mr. Pearson gave the results he had reached 

 in a study of the great raised beaches of 

 Europe and America. Attention was called to 

 the fact that up to the present time too little 

 consideration had been given by geologists to 



