194 



A'A TURE 



[Dc 



50, I J 



organs besides foliage are found, it being by no means absolutely 

 certain that becju<e the folia;Te is identical the species are so. 

 The discussion raided liy Prof. Haughton, and continued by I'rof. 

 Duncan and Mr. Wallace, seems therefore hardly worth pro- 

 longing, since it i> based upon an assumption that is only probably 

 correct. But even if the identity were proved, a single species 

 is not satisfactory evidence of forjner temperature. 



I am indebted to Mr. Winslow Jones for the only information 

 that I have yet obtained about the growth of either species in 

 England. He recollects a small tree of A. excdsa, growing near 

 the water's edge in a garden on the upper portion of Falmouth 

 Harbour, which he believes died three years ago. He has seen 

 flourishing trees at Naples, Cintra, Malta, and Algiers, but even 

 Northern Italy seems beyond the ran^e of successful cultivati m. 

 Of the two A. Cuiiiniighcimi seems the more tender, though 

 possibly its le s symiietric growth may have excluded it from 

 many gardens. In Madeira it grows generally best close to the 

 sea and in sheltered places. 



Lindley was mistaken in regarding the two species as one. All 

 the needle-leaved (Eutacta) section of Araucaria are certainly 

 closely allied, for the species, however distinct in other respects, 

 possess two kinds of foliage, that of the young plants being 

 identical in all : yet otherwise the species are clearly and distinctly 

 marked off from each other. 



With further regard to the identification of the Bournemmth 

 folia;je with Araucaria, I find that Massalongo ^ gives an excellent 

 photograph of the same foliage Iroai Chiavon, in North Italy, 

 and of an immature cone consisting of 250 scales. Although 

 existing Sequoias have cones with from 16 to 20 scales, Schimper 

 says : " II est sans aucun doute un Seijiioia et peut-etre identique 

 au S. Sterid'crgii, Les cones ont la plus grande ressemblance 

 avec ct\i)(. An S. giganim " (Pal. Vegetale," vol. iii. p. 573). I am 

 beginning to lose all faith in the so-called science of palaeo-botany 

 as worked out by our Teutonic brethren. Not only is the above 

 quotation an absurdity, for which Heer is responsible, but I fail 

 to see any gi>od evidence to support the change made by Heer from 

 Araucaria- Sternbergii to Sequoia Steriibergii. The foliage is more 

 Araucaria like than Sequoia-like, and has been found associated 

 with an Araucaria cone, but never with any Sequoia cones. It 

 has nothing to do with the Icelandic foliage, neither witli the 

 Upper Miocene foliage from Turin, nor that from Bilin nor 

 Oeningen. The true Araucaria Sternbergii characterises a well- 

 marked horizon, that of the Newer Eocene or Oligocene in 

 Central Europe, and has been found at Barton in Hampshire ; 

 it differs from the Middle Eocene form {A. veneius, Mass.) 

 of England and Italy in the needle-like leaves hugging more 

 closely to the branchlet, as the latter differs in its turn from 

 the Araucaria of the Ores du Soisionnais, which has needles 

 very widely opened ont. This progressive change may have 

 taken ^\&ce fari passu with the changing climate. At Sheppey, 

 where foliage is plentiful, I have met with a beautifully-preserved 

 axis of an Araucaria cone with the basal scales attached, exactly 

 as we find them in the existing specie-. 



Now with regard to Mr. Wallace's letter, I pointed out in 

 N.^TURE, vok xix. p. 126, that the Tertiary fossil plants, even 

 of the Eocene, require at most an increase in temperature of 20°, 

 and that the land connection between Europe, Greenland, and 

 America, which th^re is reason to suppose existed then, would, 

 by shutting out Arctic currents, have produced more than the 

 required increment If this theory appeared for the first time in 

 my article, however clumsily I may have worded it, and if it has 

 been of use to Mr. Wallace, it i; only fair that the fact should 

 be acknDwl dged, while if it has escaped his no'.ice he will per- 

 haps pardon my now drawing his attention to it. At the same 

 time the publication of the Tertiary fl )ra of North-East Siberia, 

 which I had not theu seen, and of Saghalien, has modified the 

 views I put forward in a manner which I trust I may shortly find 

 time to explain. 1. Starkie G.\RDNER 



Chalk 



Mr. Wallace's theory that chalk was deposited in compara- 

 tively shallow water requires careful examination before it is 

 accepted by geologists. I do not think he has given sufficient 

 evidence to heir out his views which are necessary t3 his theory 

 of continents. 



M'. Wallace cites the resemblance between chalk and Globi- 

 gerina-ooze, namely — 



The similarity of the minute organisms found to compose a 



^ " Speci.nen phoiographtcun." Verona, 185;. Plate xxi. 



= Actually described as Araucarites. a useless modification in tllis itiitanc;- 



considerable portion of both deposits ; several species of Globi- 

 gerina appearing to be identical in the chalk and the modern 

 Atlantic mud ; the presence of Coccoliths and Discoliths in both 

 formations ; the abundance of Sponges in both ; the presence of 

 Purifera vitrea, the nearest representative of the Ventriculites 

 of the white chalk ; the resemblance of the forms of Echino- 

 derms ; and without attempting to reconcile the-e with a shallow 

 seadepo.it, he proceeds to state the case on the other side. 

 This consists of the difference in analysis between chalk and 

 Globigerina-ooze, the former containing more carbanate of lime 

 and less alumina, the presence of silica in the Globijerina-ooze 

 being perhaps counterbalanced by the flints in the chalk. The 

 greater proportion of alumina certainly points to different con- 

 ditions, which Mr. Wallace considers to be that chalk is the 

 very fine mud produced by the disintegration of coral-reefs, and 

 mentions a deposit resembling chalk at Oahu in the Sandwich 

 Islands and the deposit in several growing reefs, v.ithout how- 

 ever attempting to show that there is any probability that the 

 remains found in these would bear any resemblance to the 

 Sponges and Echinoderms of the chalk, or why we find no 

 remains of these Cretaceous coral-reefs. 



Mr. Wallace does not state in what the greater resemblance 

 between chalk and Globigeriua-ooze of shallow over deep water 

 consists, but he loaks on it as " weighty evidence." 



Mr. Gwyn Jeffries, he fays, finds all the MoUusca of the 

 chalk to be shallow-water forms, many living at forty to fifty 

 fathoms, some confined to still shallower waters, while deep-sea 

 forms are absent. The late Dr. S. P. Woodward considered 

 that Ammonites probably lived in water not over thirty fathoms ; 

 and these facts are as difficult to reconcile with Mr. Wallace's 

 views that chalk was deposited in a sea of not over a few 

 thousand feet as in a deeper sea. 



The rareness of corals and absence of coralline beds of the 

 age of the Lower or Upper Chalk is an important objection to 

 the theory that chalk was deposited similarly to the Oahu chalk, 

 the beds of Maestricht and Faxje being above the chalk, and 

 the former are not even conformable with it. 



The point I think is still an open one, whether we shall accept 

 Mr, Wallace's views that chalk was deposited in a comparatively 

 shallow sea and not very far from land, or in a deep sea, the 

 iuamense break between the chalk and Eocene beds giving ample 

 time for very considerable alteration to have taken place in the 

 disposition of land in the interval. I send this letter in the hope 

 that a discussion on the point may elicit ne^v facts bearing on the 

 subject. S. N. Carvalho, Jun. 



8, Inverness Terrace, Kensington Gardens, W. 



On Kstimating the Height of Clouds by Photography 

 and the Stereoscope 



The great practical value of meteorological science and the 

 desirability of extending its usefulness by the collection of data 

 relating to atmospheric current will perhaps be sufficient excuse 

 for asking attention to anything likely to promote this end. 



In studying the currents and other peculiarities of the atmo- 

 sphere a method of estimating the height, m otion, and character, 

 as also the position with respect to each other, of each stratum 

 of cloud, is a requirement of almost paramount importance, the 

 value of the means employed being proportional to the number 

 of particulars provided in its record, and the facility with which 

 any set of observations can be compared to another at any future 

 period. With such ever-changing subjects as clouds in constant 

 motion, and having no strongly-defined marks, the use of theo- 

 dolites is almost out of the question, and the sextant and mirror 

 process for similar reasons would be a very tedious operation. 



These considerations have induced me to endeavour to make 

 use of photography and the stereoscope, the former to secure a 

 couple of simultaneously-exposed photographs at the extremities 

 of a base line, and the latter to observe them reproduced 

 apparently solid for the respective distances of the points com- 

 posing the picture to be measured when superimposed on a scale 

 of distances and ]ilaced in it. The base line is thus practically 

 reduced to the width of the eyes, and tae difficulties arising from 

 motion eliminated. 



The recording apparatus consists of a base 50 or 100 feet long, 

 constructed of wood and turning on a pivot at the centre of its 

 length, its extremities being suitably supported by a framework 

 of wood or other material upon which they could easily roll. 

 The small cameras for the ends of this are each to be hinged at 

 the back of its base to a second board having a graduated 

 quadrant and rackvvork erected from one of its sides for adjusting 



