April 26, 1877] 



NATURE 



55, 



THE ''LOST ATLANTIS" AND THE 

 " CHALLENGER " SO UNDINGS ' 



IT may perhaps not be at first apparent what is the 

 connection between those tubes and masses of metal 

 and other apparatus on the right ard these fossil leaves in 

 the cases on the left. Those are some of the sounding 

 apparatus used on board the Challenger in her four 

 years' voyage. They have been brought from the gal- 

 leries of the Loan Collection of Scientific Apparatus, where 

 they are deposited by the Admiralty, into this theatre, 

 in order to illustrate the method by which deep-se\ 

 soundings and temperatures are ascertained. It is the 

 results obtained from soundings in the Atlantic Ocean 

 alone that we shall consider this evening. While the 

 working out of these results, as shown in the diagram, 

 has been accomplished by the staff of the Challem^er, 

 there are some few other ships to which passing allusion 

 will have to be made. These fossil leaves, deposited by 

 Mr. J. Starkie Gardner, F.G.S., are also brought in from 

 the Loan Collection. It is not these particular leaves we 

 have to consider ; these are all English : but we shall 

 have to consider the teachings of collections of leaves 

 similar as regards their manner of preservation, obtained 

 from different parts of Europe and America. There are no 

 specimens at present in the collection besides these, though 

 until recently there was the small typical collection of the 

 Baron von Ettingshausen. These English specimens 

 will, however, serve our purpose very well as illustrations 

 to convey an idea of what Tertiary fossil leaves look like. 



The connection between these two subjects is here. We 

 are going to consider certain past vegetations which are 

 made known to us by their fossil remains. The study of 

 some of them led Prof linger by a process of reasoning 

 that will be presently indicated, to the belief that there 

 existed in Tertiary times land between Europe and 

 America by which the ancestors of the plants gradually 

 travelled from America to Europe. It is now seventeen 

 years ago that Prof. Unger proposed to call this hypo- 

 thetical land the Island of Atlantis ;— the sunken island 

 or lost island of Atlantis. It was, no doubt, what our 

 American cousins would call " a big thing " for a 

 botanist to do, to " create" a former land in mid-ocean 

 simply because he wanted it to account for the migra- 

 tion of the ancestors of fossil plants he had studied, 

 and to do so without a particle of physical evidence. 

 It was the first time in the history of geological science 

 that so bold a step had been taken. The arguments by 

 which Unger arrived at his conclusions were criticised 

 at the time and another route for migration by the Pacific 

 was suggested. 2 Whatever may be opinions as to the 

 value of the evidence on which Prof. Unger based his 

 " lost Atlantis^' we now know from the Challenoer work- 

 ing out of soundings that not only a " sunken island," but 

 a ridge does lie in mid-AiIantic between the Old and New 

 World. 



Our subject groups itself into three divisions :— (i) 

 Tertiary fossil plants ; (2) Deep-sea soundings ; (3) the 

 "Atlantis ridge." 



[The lecturer then turned to the fossil leaves, and de- 

 scribed their manner of preservation and the conditions 

 under which they are met with, and referring to diagrams 

 and tables explained the meaning of the word Tertiary.] 



No one now doubts these are really the remains of plants 

 that grew and are not lapides sui generis. In comparing 

 them with living plants and determining their affinities there 

 are many difficulties to be encountered. The remains them- 

 selves are often fragmentary. Even when they are tolerably 

 ! perfect the comparisons have to be made for the most 

 part with specimens in herbaria, and the variations seen 



» Ab- tract of a lecture given in connection wi;h the Loan Collection of 

 Scientific Apparatus at South Kensington, March 31, 1877, by W. Stephen 

 Miichelt, M.A.. LL B. , r, ^ . ,- 



» Prof Oliver, Nat. Hist. Rev. Ap., 1862, Prof. Asa Gray, Me/n. Am. 

 Acad., N. S., vol. vi. p. 377- 



in the few leaves of a specimen often suggest that varia- 

 tions from different parts of the tree may be considerable. 

 With fruits and with ftrns preserving the fructification, 

 the determination is safer, but with leaves alone, while in 

 some well-marked cases there can be hardly a doubt, in a 

 large proportion of cases the doubt is great. When the 

 lecturer first paid attention to the Low^r Ba^^shot flora, 

 fourteen years ago, he thought, as many unacquainted with 

 the subject might think, that with such herbaria as at 

 Kew and the British Museum the work of comnarison 

 would be simple. The riches of these places will soon 

 show, however, that a wide experience and a trained eye 

 are needed to refer to all the species, frequently of orders 

 and genera widely separated in the natural classification, 

 whose leaves resemble a fossil leaf under consideration. 

 Those who may try the work will more readily under- 

 stand how it was that a few years ago not a single 

 English botanist of note was willing to attach any im- 

 portance to the determinations based on fossil leaves 

 alone. 



Matters are looking more hopeful now, partly because 

 more perfect and well-marked specimens are being 

 frequently added to museums and private collections, 

 and partly because the writers of monographs on any 

 living order are now beginning to adopt the plan of 

 adding what is known abjut its fossil forms. There can 

 hardly be a doubt that the solid reliable progress in the 

 determination of fossil leaves is to be made alone by 

 botanists who select a particular group of plants for ex- 

 haustive study, and include such fossil forms as they find 

 no hesitation in admitting. General botanists of even 

 great experience may make good guesses, but nothing 

 shoit of the determination of a specialist can be regarded 

 as absolutely safe, even if that may be considered so. 



While the feeling of English botanists a few years 

 ago was as described, there were on the Continent 

 some few whose hesitation with regard to fossil leaves 

 did not prevent them from trying what could and 

 what could not be done in the way of identification, 

 [The lecturer then referred to the work of continental 

 botanists, especially of Heer and Unger, and alluded to 

 the confirmatory evidence which in some cases had 

 occurred of fruits being found subsequently from the 

 same locality as leaves, whose determination had been 

 attempted.] Unger compared the Tertiary flora of 

 America with that of Europe, and in i860, in a lecture 

 called '■ Die versunkene Insel Atlantis," made a com- 

 parison between the two, and detailed the steps by which, 

 after twenty years' study, he had been led to the conclu- 

 sion that the European Tertiary flora had a North 

 American character. There have been two theories r>;- 

 specting the origin of plants in particular areas. One is 

 that the plants of that area have been created there as 

 fully developed as met with ; another is that they have 

 been partly the result of evolution in the same district, 

 and partly or entirely the result of immigration from other 

 districts. [Starting with familiar illustrations of the 

 effects of climate on plants, the lecturer proceeded to 

 show how plants retreated before climatal conditions that 

 were hostile to them and spread where the conditions 

 were favourable, in some cases changing the elevation at 

 which they grew, in others changing their area.] It was the 

 consideration of the migration of the plants that led Prof. 

 Unger to believe that a high proportion of the European 

 Tertiary forms had come from North America. 



It would occupy too much time and would fulfil no useful 

 purpose in a popular lecture like this, to give in detail the 

 data on which he based his conclusions, A rJsitmS of 

 them in a form convenient for reference may be found in 

 a translation of his lecture in the Journal of Botany of 

 January, 1865. Believing the evidence was sufficiently 

 strong that the Tertiary plants he studied had come from 

 North America, he proposed a hypothetical land bet^veen 

 the two as the route by which they had travelled. 



