258 



NATURE 



\yuly lo, 1879 



conceivable conditions of climate could permit the vegetation of 

 the neighbourhood of Disco in Greenland to be identical with 

 that of Colorado and Missouri, at a time when little difference of 

 level existed in the two regions. Either the southern flora 

 migrated north in consequence of a greater amelioration of 

 climate, or the northern flora moved southward as the climate 

 became colder. The same argument, as Gardner has ably 

 shown, applies to the similarity of the tertiary plants of tem- 

 perate Europe to those of Greenland. If Greenland required a 

 temperature of about 50°, as Heer calculates, to maintain its 

 ' miocene ' flora, the temperature of England must have been 

 at least 70°, and that of the South-western States still warmer." 

 The author then speculates upon the former migrations of 

 plants, and although he does not a<;sign, like Saporta, an 

 unvarying north and south direction, he believes that in most 

 instances these were the lines upon which they moved. He also 

 places a cold period between the middle cretaceous (upper 

 cretaceous of Atane, Heer) and the lower eocene (Greenland 

 miocene, Heer), which had not been previously noticed. 



We would here remark that there is, in like manner, evidence 

 of a cool period at the base of the English eocene. Either one 

 relatively cool period existed at the close of the upper cretaceous 

 of America, and another at the base of the English eocene, or 

 else too great an age is assigned to the American series. The 

 latter supposition is supported by Lesquereux's researches. The 

 beds showing the more temperate conditions on the two con- 

 tinents are either contemporaneous or else a geological interval 

 exists between them. Much more evidence is required before 

 the correlation of the American and European cretaceous and 

 tertiary rocks can be finally determined, and it is satisfactory to 

 know that Dr. Hayden is collecting evidence on the snbject. 



The lower eocene flora of Greenland ' ' established itself in 

 Greenland, and probably all around the arctic circle, in the 

 warm period of the earliest eocene, and as the climate of the 

 northern hemisphere became gradually reduced from that time 

 to the end of the pliocene, it marched on over both continents 

 to the southward, chased behind by the modern arctic flora, and 

 iventually by the frost and snow of the glacial age. This history 

 may admit of correction in details ; but so far as present know- 

 edge extends it is in the main not far from the truth." 



Space does not permit us to reprint the pages devoted to the 

 various theories that have been put forward to account for former 

 vicissitudes of climate. While allowing due weight to CroU's 

 ingenious and well known theories, and to the larger proportion 

 in the past of carbonic dioxide, he nevertheless is convinced of the 

 sufficiency of the Lyellian theory of former altered distribution 

 of land and water to account for all the facts hitherto observed. 

 Tlie author conceives, however, that in some recent publications 

 the Lyellian theory has been misconceived, but this is not exactly 

 the case. What he here terms the Lyellian theory was really shared 

 by many contemporary writers on physical geography, and is, that 

 when land surfaces are aggregated round the equator and the 

 polar oceans are wide and open, a hot period rcFults, and that the 

 reverse distribution induces cold, thus giving to land the heating 

 power. The more recent theory is a modification of this, requiring 

 masses of water, warmed under the equator, to circulate, un- 

 chilled by polar currents, and the polar oceans to be dry or else 

 more or less closed in by land. This view he adopts. 



" If North Greenland were submerged, and low land reaching 

 to the south terminated at Disco, and if from any cause either 

 the cold currents of Baffin's Bay were arrested, or additional 

 warm water thrown into the North Atlantic by the Gulf Stream, 

 there is nothing to prevent a mean temperature of 45° Fahrenheit 

 from prevailing at Disco ; and the estimate ordinarily formed 

 of the requirements of its extinct floras is 50',' which is probably 

 above rather than below the actual temperature required." 



Professor Dawson believes that to whatever causes the cold 

 periods may be traced, they drove the warm temperate flora to 

 the south, unless protected in insular spots by warm currents, 

 and that on the return of warmth the plants would return 

 northward. 



"If, however, our modern flora is thus one that has returned 

 from the south, this would account for its poverty in species as 

 compared with those of the early tertiary. Groups of plants 

 descending from the north have been rich and varied. Return- 

 ing from the south they are like the shattered remains of a 

 beaten army. This at least has been the case with such retreat- 

 ing floras as those of the lower carboniferous, the permian, 



' Heer. See also papers by Professor Haughton and by Gardner in 

 Nature for \'i^i. 



and the Jurassic, and possibly that of the lower eocene of 

 Europe." 



The great stretch north and south of the American continent 

 favoured these migrations, and " is also connected with the inte- 

 resting fact that, when new floras are entering from the arctic 

 regions, they appear earlier in America than in Europe ; and 

 that in times when old floras are retreating from the south, old 

 genera and species linger longer in America. Thus, in the 

 Devonian and cretaceous new forms of those periods appear in 

 America long before they are recognized in Europe, and in the 

 modern epoch forms that would be regarded in Europe as 

 miocene still exist. Much confusion in reasoning as to the 

 geological ages of the fossil floras has arisen from want of 

 attention to this circumstance." 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



In reply to a question in the House of Lords the other day 

 the Duke of Richmond and Gordon stated that it was only in 

 187s that it was decided to add agriculture to the syllabus of the 

 Science and Art Department. At the first examination in May, 

 1876, there were only 150 cancidates. By the following year 

 72 classes had been established, and the number of candidates 

 rose to 800. In 1878 the classes had increased to 91, and the 

 candidates for examination to 1,265, and this year the number of 

 classes had reached 147 ; the number of persons under instruc- 

 tion was 2,839, of whom 2,193 came up for examination. I'rof. 

 Tanner reported that the results of the examination wtre very 

 satisfactory. Fifty selected teachers, it was stated, had been 

 brought up to London to undergo a com-se of tr.uning at the 

 expense of the department. 



The two silver medals which are annually given by the Royal 

 Geographical Society to those candidates whom the examiners 

 deem to be most proficient in geography at the Cambridge Local 

 Examinations have this year been awarded as follows : — Physical 

 Geography, J. R. Davis ; Political Geography, Miss Helen 

 Jones. This, we believe, is the first occasion on which a medal 

 has been awarded to a lady. 



The professors of the Paris Museum of Natural History 

 having to present to the Minister of Public Instruction the names 

 of two candidates for the lectureship of Comparative Anatomy, 

 vacated by the death of M. Paul Gervais, have selected M. 

 Georges Pouchet for their first candidate, and M. Jourdain for the 

 second. The appointment of the former is quite certain. 



The number of students at the German Universities during 

 the winter semester 1878-9 was 18,770. Berlin stands at the top 

 of the list with 3,213, while Rostock had only 161. 



SOCIETIES AND ACADEMIES 

 London 

 Royal Society, June 19. — "Relations between the Atomic 

 Weights and certain Physical Properties (Melting and Boiling 

 Points and Heats of Formation) of Elements and Compounds." 

 By Thomas Carnelly, D.Sc, Assistant Lecturer on Chemistry in 

 Owens College, Manchester. Communicated by Prof. H. E. 

 Roscoe, F.R.S. 



Anthropological Institute, June 24. — Mr. John Evans, 

 F.R.S. , vice-president, in the chair. — The election of the fol- 

 lowing new Members was announced : — Mr. F. Du Cane Godman, 

 F.L.S., F.Z.S., and Mr. Percy Cotterill Wheeler, Bengal Civil 

 Service. — Prof. W. H. Flower, F.R.S., read a paper on the 

 osteology of the natives of the Andaman Islands. There are few 

 people whose physical characters offer a more interesting subject 

 for investigation to the anthropologist than the native inhabitants 

 of the Andaman Islands. Purity of type, due to freedom from 

 mixture with other races for an extremely long period, owing to 

 their isolated position and their inveterate hostility to all intruders 

 on their shores, and exemplified in the uniformity of their physical 

 characters, is to be found among them, perhaps in a more complete 

 degree than in any other group of mankind. The type, more- 

 over, is an extremely peculiar one, presenting a combination of 

 characters not found in any race of which we have at present 

 materials for a satisfactory comparison. It is, indeed, probable 

 that the more or less mixed and now scattered fragments of 

 Negrito population, found in the interior of various islands of 

 the Indo-Malayan Archipelago, and even upon some parts of the 



