326 



SCIENTIFIC NEWS. 



[Sept. 21, I S 



tain chains, the origin of volcanoes, and the probable 

 causes of earthquakes, the structure of the Alps, and the 

 foldings of the chalk. 



Less in conformity with the fundamental objects of the 

 Congress, but having nevertheless a relation to them, 

 were the memoirs on the Felspars, on the alteration of 

 superficial deposits, on the employment of the polarising 

 microscope, on the propagation of heat in rocks, and other 

 special subjects. 



The Congress of Bologna.- — In the fine volume con- 

 stituting the account of the meeting held at Bologna is 

 contained the report of the International Jury appointed 

 to judge the competition for rendering the colours and 

 geological signs uniform, for which the King of Italy had 

 generously offered 5,000 francs to be given for the best 

 memoirs deemed practically applicable. 



Six memoirs were received, of which the three prize 

 ones are published with coloured illustrations which leave 

 nothing to desire. The authors of these were of opinion 

 that though the solar spectrum is a very advantageous 

 fixed base, the scale of colours was insufficient, and that 

 it would be necessary to introduce complementary colours 

 or such as had a relation to the primary ones. The divi- 

 sions, in fact, of the sedimentary beds are so numerous 

 that it would be necessary to employ not only these 

 colours, but also many shades of the same colours or of 

 different hatching, reserving rose-colour for the Archaean 

 crystalline schists. 



It was agreed to use for the eruptive rocks, strong and 

 brilliant tints of red, green, or purple, the intensity of 

 which would render them easily distinguishable from the 

 colours of the primary sedimentary rocks and from the 

 clear colour of the schists. It was desired too to dis- 

 criminate between the acid and the basic rocks, both by 

 their petrological composition and by their age, in using 

 different shades of the same colours with coloured dots 

 or by hatching of different kinds, and with the letters of 

 the Greek alphabet. It is proposed to show thus by 

 symbols the principal varieties of the granitic, porphy- 

 ritic, trachylic, andesitic, basaltic, and other rocks ; but 

 the varieties are so numerous that it would be difficult to 

 know where to place the limits, and according to one of 

 these plans it would be necessary to use seventy-six signs 

 and hatchings of different colours. You will be able to 

 judge of the different methods proposed by. the fine 

 plates by which the reports are illustrated. The sections 

 taken in the mountains of Switzerland and others which 

 serve as examples produce an excellent effect. Conven- 

 tional signs are also used to indicate the inclination and 

 direction of beds, faults, fossiliferous places, cold, warm, 

 and mineral springs, travertines, quarries, mines, etc. A 

 geological map will thus be a veritable hieroglyphic 

 chart possessing a universal meaning. 



As a result of the discussions held at Bologna, and 

 in order to make a practical application of them, it was 

 decided to publish a Geological Map of Europe on the 

 scale of lo „^ 0( , , in which the signs and colours definitely 

 adopted by the Congress should be employed. This 

 map, already far advanced towards completion, is under 

 the direction of a Committee at Berlin. 



With respect to the reports on the uniformity of 

 Geological Terms, they have been received from nine 

 national Committees, namely, Austria, Belgium, Spain, 

 Portugal, France, Great Britain, Hungary, Italy, Russia, 

 and Switzerland. Besides these there are eleven from 

 individual members. One might well imagine that among 

 so many opinions all would not agree; but from the 



good-will that every one has brought to the question, 

 although some discord has occurred on points of detail, 

 they were almost unanimous on essential matters, and a 

 general agreement for Stratigraphic Terms has been 

 arrived at, such as group, system, series etage, and for 

 Chronological Terms, such as era, epoch, age, etc., leav- 

 ing to future Congresses the considera'in cf Gertain 

 other trifling points. This subject reminds me, gentle- 

 men, of a difficult question which you havj to face. If 

 your resolutions are voted by the vo : ces of all the mem- 

 bers of the Congress, the result can scarcely help show- 

 ing the effect of the variable number of the nationalities 

 according to the country in which the congress is held. 

 For example, at Bologna there were 149 Italian members 

 and 19 English ; at Berlin, 163 Germans and n English ; 

 here the numbers of English and foreign geologists pre- 

 sent is still more considerable than at preceding Con- 

 gresses. Therefore if all vote, the opinion of the place 

 in which the Congress is held will predominate too 

 much, unless you find means of placing limits to it. 



Thanks to the fairness of the Council at Bologna, the 

 greater part of the Resolutions were passed unanimously ; 

 some few having been referred back to the various Com- 

 mittees for further deliberation. 



As to the stratigraphical divisions, it was resolved : 

 (1) That the term " Group ' shall be applied to each of 

 the great divisions of the Primary, Secondary, and Ter- 

 tiary rocks. (2) That the sub-divisions of these groups 

 shall be called " Systems." Thus you have Primary 

 Group, or Palaeozoic, and Silurian System, Jurassic 

 System. (3) To the first order of divisions of the 

 systems,the term series will be applied (Oolitic series), to 

 the divisions of the second rank the term " Etage," and 

 to those of the third order the word " Assise." The unit 

 of the stratified masses is the stratum or bed. With 

 regard to a word much used in England, and dating from 

 the primary time of geology, the word " Formation," the 

 majority of the Congress decided not to employ it in 

 the sense of the French " Terrain " as we generally do, 

 but only in the sense of origin or mode of formation, 

 so that we should say of a bed that it is a marine forma- 

 tion, or fluviatile formation, etc. We must, therefore, 

 endeavour to find some other word to replace the habitual 

 "Chalk Formation," London Clay Formation, etc. 



For the Chronological divisions corresponding to those 

 of the stratigraphy, it has been proposed that : 

 (1) " Era " shall correspond to " Groupe," as " Primary " 

 or " Secondary Era ;" (2) "Pe"riode"to " Systeme," as 

 "■ Silurian Period," Cretaceous Period;" (3) "Epoch" to 

 " Series," as " Inferior Oolite Epoch ; " (4) " Age " to 

 "Assise," as " Portlandian Age." 



On the subject of colours and symbols, the final deci- 

 sion was delivered to the committee of the geological 

 map, and with respect to the rules to be followed in the 

 nomenclature of species, it was resolved that the name 

 given to each genus and each species shall be that by 

 which they were earliest designated, subject to the con- 

 dition that the characters of the genus and species have 

 been published and clearly defined. The priority will 

 not go back beyond Linnaeus, 12th edition, 1766. 



At the Bologna Congress there were only four special 

 and local memoirs, and those were only produced in 

 support of collections and documents which were exhi- 

 bited. 



Congress of Berlin. — The official account of this 

 meeting has only been published a few days. I greatly 

 regret that I have not been able to avail myself of it, for 



