ya7i. 25, 1877] 



NATURE 



281 



tending to make their preservation difficult, which may 

 perhaps be taken into account. 



Some kinds of coniferous plants resist decay, when im- 

 mersed in water, more completely than do almost any 

 dicotyledons, and this resistance may, owing to their 

 resinous nature, be very greatly increased when the im- 

 mersion is in sea-water. This supposition is borne out 

 by a fact I have noticed, that in some Eocene beds, such 

 as the marine beds at Bournemouth, the Bembridge marls, 

 the Bracklesham beds, coniferous remains preponderate, 

 whilst from the two latter places I have never seen re- 

 mains of dicotyledons at all, although there is evidence in 

 these cases that dicotyledons were abundant on all 

 surrounding land areas. This may partly account for 

 their complete absence in marine cretaceous rocks in 

 England, where, as in the gault, &c., foliage, fruit, resinous 

 gums in the form of amber, remains of coniferae, are 

 preserved. The foreign cretaceous rocks, in which an 

 abundance of dicotyledons is met with, are principally of 

 fresh-water origin. 



It should be borne in mind that our Chalk period con- 

 tains a deep sea fauna, and we have no record in England 

 as to what were the prevailing contemporaneous shallow 

 water forms of life in other regions. I have great doubts, 

 however, as to the correct position of many of the foreign 

 so-called cretaceous beds. Those of America, from which 

 most of the list of dicotyledons of this period is derived, 

 appear to me, from the character of their fauna, to be 

 either Lower Eocene, or at most filling in the gap between 

 our chalk and London clay. Most of the shells have a 

 marvellously Eocene-like aspect, and I take it that the 

 presence of an ammonite, and some few other forms of 

 shells, which in England do not range above the Chalk, 

 should not be taken as conclusive evidence of the anti- 

 quity of the bed, as although migrated from our seas, they 

 may very well have lived on in other regions. It is incon- 

 sistent to assume that no ammonite lived on in any part 

 of the world to a more recent period than that of our 

 Chalk ; the finding of pleurotomaria and other supposed 

 extinct cretaceous shells in Australian waters, should not 

 be forgotten. The same doubts apply to many of the 

 European leaf deposits ; many of these are isolated 

 patches, and their age has been inferred rather from 

 the character of the leaves than from their strati- 

 graphical position. The age of many of the so-called 

 Miocene leaf-beds is admitted now to be extremely 

 doubtful. 



What little evidence we may expect to find in these 

 beds seems to me likely to be in favour of the theory of 

 evolution by descent, although until the flora has been 

 worked out, it is premature to offer an opinion. By far 

 the greater number of the plants belong to the lowest 

 division of the dicotyledons, the apetalce^ a minority are 

 polypetalojis, whilst none can, as far as I know, with cer- 

 tainty be assigned to the highest (according to Haeckel) 

 group, the vionopetalcE, 



Prof. Ettingshausen has traced the gradual develop- 

 ment of some of the Miocene forms into existing species, 

 notably that of Castanea atava to Castanea vescaj when 

 he was here last summer and saw my collection, he espe- 

 cially picked out the castanea from Bournemouth as 

 carrying the history of this genus a step further back, and 

 linking it with the oak — as it possesses an oak-Uke 

 character of venation. I would merely add that many 

 botanists who have studied fossil plants, as Unger, 

 Schimper, and others, are profoundly impressed with the 

 amount of botanical evidence that has already been 

 brought forward in support of the theory of evolution. 



OUR ASTRONOMICAL COLUMN 

 Red Star in Cetus.— No. 4 of Sir John Herschel's list of 

 red stars at p. 448 of his Cape Observations is placed by him in 

 R.A. ih. 19m. 87s., N.P.D. 123° 26' i" for 1830, with the 



remark " most beautiful orange red. Two observations," and 

 he estimated it 6m. Dunlop in his catalogue of 253 double and 

 triple stars in vol. iii. of the Memoirs of the Royal Astronomi- 

 cal Society, gives the position of a highly-coloured object thus : 

 for 1827, R.A. ih. 19m. 43s., N.P.D. 123° 31', and calls it "a 

 very singular star of the seventh magnitude, of an uncommon 

 red purple colour, very dusky, and ill-defmed ; " he made three 

 observations upon it, and notes that it had a small star preceding 

 and another following it. We may presume that these stars are 

 identical, with an error of position on the part of one or other 

 observer, most probably on Dunlop's, whose catalogue contains 

 a number of errors ; and it may also be supposed that this is the 

 star spectroscopically examined by Secchi, which he calls No. 1 1 

 of Schellerup's catalogue of red stars, but places in 35' 17' S. 

 declination (A.N. 1737), perhaps through a misprint. In this 

 state of uncertainty as to the star's true place, meridional observa- 

 tion appears very desirable. So far we believe it is not to be found 

 in any catalogue, founded on such observations ; it does not 

 occur in the zones published in the Washington volumes 1869-71, 

 a most valuable series, nor in those of Prof. Ragona in the Giornale 

 Astronomico e Meteorologico del R. Osservatorio di Palermo, 

 vols. i. and ii., neither is it found in the southern catalogues of 

 the Cape, Madras, or Melbourne Observatories. Sir John 

 Herschel's place reduced to 1877-0 is R.A. ih. 21m. 190s., 

 N.P.D. 123° 11' 16". Secchi says of the star he examined, 

 " couleur rose ; spectre a zones discontinues." 



Variable Stars. — There is considerable probability that 

 Lalan.de 12863-5 should be added to the list of variable stars. 

 His estimates of magnitude are 64 and 84 ; it is 6 on Harding's 

 Atlas and in Argelander, 67 in Heis, 7*3 in the Durchmus' 

 terung, but does not occur in Piazzi, Bessel, or Santini. Piazzi 

 has a star of the ninth magnitude about i^° distant (VI. 190), 

 which, oddly enough, he places in the Lynx. The position of 

 Lalande's star for the beginning of 1877 is in R.A. 6h. 35m. 23s., 

 N.P.D. 83° 32-3'. 



Will some one of our southern readers record the actual 

 magnitude of jU Doradus ? At present we have the following 

 estimates indicating a long period of variation. La Caille 5m. 

 about 1751, Brisbane 6m. about 1825, Jacob 9"5m. in 1850 and 

 9-2m. in 1855 ; while Moesta states that between February, 

 1 860, and January, 1861, he had always found it 84m. or 9m. 

 The law of variation may be similar to that of 34 Cygni, P Cygni 

 of Schonfeld, the so-called Nova of 1600. 



A Fifth Comet in 1851. — In a small tract entitled " Rag- 

 guagli Popolari sulleComete Periodiche," by Prof. Ragona, pub- 

 lished at Palermo, in 1855, there is reference to a comet stated to 

 have been discovered at Rome by Prof. CalandreUi, director of the 

 Pontifical Observatory, iu the morning twilight on November 30^ 

 185 1, which both the discoverer and the writer of the tract con- 

 sidered to be the short-period comet of Brorsen, due in perihe- 

 lion in the autumn of that year. By comparison with B.A.C. 

 4798, the following position resulted : — 



1 85 1, November 29, at I7h. 32m., M.T. at Rome. 

 Right Ascension, I4h. 21m. 38s. Declination, + i' 47' 2". 

 This position Prof. Ragona compares with the elements of 

 Brorsen's comet according to Dr. van Galen, and found the dif- 

 ferences between calculation and observation -t- 35' 27" in R.A., 

 and + 11' i" in declination. But notwithstanding this approxi- 

 mation, it is certain it was not the periodical comet of Brorsen 

 that was observed by CalandreUi, Dr. van Galen's prediction 

 having been vitiated by a serious error of calculation, so that, 

 instead of arriving at perihelion on November 10, the date as- 

 signed by him in Ast. Nach., No. 782, the comet passed that 

 point in its orbit about September 25, and consequently on 

 November 30 was far removed from the position of the body 

 observed by CalandreUi, which was therefore a new comet. 



