Nov. 13, 1873J 



NA TURE 



35 



PHYSICAL GEOGRAPHY AND TERRESTRIAL 

 MOLLUSC A OF THE BAHAMA ISLANDS 



A PAPER on this subject has recently been communicated to 

 7^ the Lyceum of Natural History, New York, by Mr. 

 Thomas Bland. 



The northern end of the Bahama group lies opposite southern 

 Florida, and from this point the islands stretch off in a double 

 series, nearly parallel to the trend of Cuba and San Domingo, 

 and terminate, properly, in the Turk's Island Bank, on which 

 are the last and most easterly of the chain, which extends about 

 600 miles, from within 70 miles of the coast of Florida to within 

 100 miles of that of San Domingo. 



Several banks are distinguishable, and the islands are gener- 

 ally on the windward sides of these, never exceeding 200 ft. in 

 height, and being almost universally environed with reefs or 

 shelves of rock, which extend often to a considerable distance 

 and usually terminate abruptly. 



The geological formation appears to resemble that of Bermuda ; 

 their form and surface condition being largely due to prevailing 

 winds and currents, but also owing much, probably, to the con- 

 figuration of the land on which the coral reefs were built up. 



Lieutenant NeUon speaks of the Bahamas as the Gulf Stream 

 Delta ; thrown down where the stream receives a check from 

 the Atlantic on emerging from the Gulf of Mexico. 



In a communication to Nature, vol. vi. p. 262, Mr. Jones 

 furnished evidence of the subsidence of the Bermudas. In exca- 

 vations made for the great dock e.g., there was found, at 46 ft. 

 below low-water mark, a layer of red earth, containing remains 

 of cedar trees, and resting on a bed of compact calcareous sand- 

 itone. 



Mr. Bland examines the evidence afforded (as to subsidence), 

 by the distribution of land shells on the Bahama Islands. The 

 total number of species known is about 80. 



Judging from both operculates and inoperculates, the land- 

 shell fauna of the Bahamas is essentially West Indian, and that 

 of the Great Bank (especially), closely allied to the Cuban fauna. 

 Mr. Bland gives a list of inopercalate species common to the 

 Bahamas, the adjacent continent, Bermuda, and certain of the 

 West Indian Islands ; which shows in a marked manner the 

 alliance referred to. 



The banks and islands of the Bahama chain diminish in size 

 to the south-east, indicating greater subsidence in that direction. 

 Similarly, the submerged Virgin Island bank, Sombrero and 

 the Anguilla bank, terminate the parallel West Indies chain 

 eastward from Cuba ; and in Anguilla have been found remains 

 of large extinct mammalia which must have inhabited at one 

 time a much more extensive area. 



The author criticises Dr. Cleve's geological grouping of the 

 slands north of Guadeloupe (in two groups, one comprising 

 Bahamas, of post-pliocene date, another of the tertiary Eocene, 

 Miocene, and Pliocene), and points out that the land shell fauna 

 of Saba, St. Eustatius, St. Kitts and Nevis, of Redonda and 

 Montserrat, and of Barbadoes and Antigua, is, in common with 

 most of the islands to the south, to and inclusive of Trinidad, 

 distinct from the fauna of the islands between and inclusive of 

 the Bahamas and Cuba, and the Anguilla bank, on which are 

 Anguilla, St. Martin and St. Bartholomew. This well-defined 

 line of separation must be considered in connection with the 

 past and present geological history of the islands. 



Dana traces parallel bands of greater or less subsidence in the 

 Pacific Ocean, and analogous conditions in the Atlantic ; the 

 subsidence was probably, he says, " much greater between 

 Florida and Cuba than in the Peninsula of Florida itself, and 

 greater along the Carribbean Sea parallel with Cuba, as well as 

 along the Bahama reefs than in Cuba." Recent soundings, 

 cited by Mr. Bhmd, con£rm this view. 



SCIENTIFIC SERIALS 

 Ocean Highiiiays, November. — In an article on " The Results 

 of the Arctic Campaign, 1873," it is shown that the right direc- 

 tion for Arctic Exploration has been unmistakeably indicated, 

 further proofs have been afforded of the practicability of attaining 

 an advanced position by following that direction, and additional 

 evidence has been accumulated against the route advocated by 

 "unpractised theorists." These conclusions are rightly drawn 

 from the eminently successful results obtained from the Polaris 

 expedition and from Captain Markham's fruitful cruise in the 

 Arctic, as contrasted with the comparatively unsuccessful at- 

 tempts made in the Spitzbergen direction by the Swedish Expe- 



dition and that of Mr. Leigh Smith. "The learned societies 

 will be able to make their appeal to the Government with even 

 stronger and more cogent arguments than were at their disposal 

 in the end of last year ; while in the present Prime Minister and 

 Chancellor of the Exchequer they have an old and staunch 

 supporter of Arctic expeditions, and one who has studied their 

 histoiy and appreciated their uses." There is a carefully con- 

 structed map illustrative of Captain Markham's voyage in the 

 Arctic. Other articles are, " On the Distribution of Coal in 

 China," by Baron von Richthofen ; " South American Progress " 

 (Argentine Republic), by F. J. Rickard ; " Highways and Bye- 

 ways of Naval History," the first of a series of articles by Mr. 

 R. Lendall. 



Gazctta Chimica Italiaiia, Fascicolo V. and VI. — The number 

 commences with a paper on Santonin, by S. Cannizz.aro and 

 F. Sestini. Santoninic acid is described ; it is derived from 

 santonin by the addition of one molecule of water to one of 

 santonin. The addition is effected by acting on santonin by 

 means of a warm aqueous alkaline solution. The formula of 

 the acid is CisH.^nO^. = CjsHigO., + H, O. The properties of 

 the acids and its salts are described, and the action of nascent 

 hydrogen on santonin is then considered. — New researches on 

 benzylated phenol, by E. Paterno and M. Fileti. — On the 

 chemical analysis of some wines grown in the Veronese province, 

 by Prof G. Dal Sie. The wines in question seem to be some- 

 what strong, the percentage (volume) of alcohol ranging from 

 g'4 to i6"4. Very voluminous tables of analyses are given. — -A 

 paper on the dry distillation of calcic formate, by A. Lieben and 

 E. Paterno concludes the original portion of the number, which 

 concludes with 155 pages of abstracts from foreign journals. 



Annalcn dcr Chcinie icnd Pharinacic, Band 168, Heft 2 and 3, 

 August 30. — The number commences with two papers from 

 Prof. Beilstein's laboratory. The first by W. Hemelian is on a 

 new method of preparing the sulpho acids ; the method in ques- 

 tion is a modification of that of Strecker. Dr. E. Wroblevsky 

 communicates a paper on certain haloid derivatives of toluol ; he 

 describes a number of the meta-brom-toluol compounds, and also 

 deals with the para-brom-toluols and the tri-brom-toluols. — 

 The other papers are : On selenic acid and its salts, by Dr. v. 

 Gerichten. He finds that the seleniates are all isomorphous 

 with the corresponding sulphates, and the double salts also agree 

 with the double sulphates. — On the action of tri-sulpho-carbonate 

 and sulpho-carbaminate of ammonium on aldehyde and acetone, 

 by E. Mulder. A number of the compounds resulting from these 

 reactions are described. — On a new mode of forming ortho- 

 toluilic acid, by R. Fittig and William Ramsay. On meta- 

 toluic acid, by C. Boettinger and W. Ramsay. — On ethyl and 

 di-ethyl-allyamine, byA.Rinne. Ethyl-allylamine is isomeric with 

 methyl crotonylamine, the two bodies having the formulae — 

 ( C3H5 ( C^^^ 



N ^ CHj and N \ CH3 respectively. 

 ( H ( H 



The author-describes several of the salts of the former. Di-ethyl- 



' i C:,H, 

 allylamine N < CH^ is produced by the action of ethyl iodide 



( C0H5 

 on allylamine. The author describes it and its hydrochlorate 

 and platino-chloride. — Researches on the isomers of cresol with 

 regard to their occurrence in coal tar, by M. S. Southworth. — 

 Researches on sorbic acid by E. Kachel and R. Fittig. — The 

 number concludes with a very lengthy paper on the actions oc- 

 curring in the inner non-luminous flame of the Bunsen burner, 

 by R. Blochmann. The author has collected and examined the 

 gases from various parts of the flame, and the memoir is illus- 

 trated with two plates showing tlie apparatus used, and the 

 flames given by the burner under various treatments, and a 

 diagram showing the percentages of CO^ and H2O, given by 

 flames when burning, at various heights above the burner up to 

 1 20 millimetres. 



SOCIETIES AND ACADEMIES 

 London 

 Zoological Society, Nov. 4. — Prof. Newton, F.R.S., vice- 

 president, in the chair. The Secretary read a report on the ad- 

 ditions that had been made to the Society's menagerie during 

 the months of June, July, August, and September. Mr. G. 

 Dawson Rowley exhibited a singular malformed variety 

 of the Domestic Duck, and the Secretary a collection of fishes 

 (containing six examples of Ceratodus forsteri) made by Mr. 



