NA TURE 



193 



THURSDAY, JANUARY 2, 1890. 



THE BERMUDA ISLANDS. 



A Contribution to the Physical History and Zoology of 

 the Sfltncrs Archipelago. With an Examination of the 

 Structure of Coral Reefs. By Angelo Heilprin, Curator- 

 in-Charge and Professor of Invertebrate Palaeontology 

 at the Academy of Natural Sciences of Philadelphia, 

 &c. With additions by Prof. J. P. McMurrich, Mr, 

 H. A. Pilsbry, Dr. George Marx, Dr. P. R. Uhler, and 

 Mr. C. H. Bollman. (Philadelphia : Published by the 

 Author, 1889.) 

 ' pHIS work is mainly the outcome of researches con- 

 •- cerning the physical history, geology, and zoology 

 of the Bermudas, which were accomplished under the 

 auspices of the Academy of Natural Sciences of Phila- 

 delphia in the summer of 1888. The author's principal 

 object was to satisfy his own mind on certain points 

 connected with the structure of coral reefs, and but little 

 zoological work was contemplated. Fortunately, how- 

 ever, the collection of zoological material proved more 

 extensive than was expected, and in this respect Prof. 

 Heilprin was greatly assisted by the students who ac- 

 companied him. 



After a pleasant chapter of " general impressions," the 

 author gives the results of his examination of these 

 islands, and then proceeds to make such a vigorous attack 

 on the views advanced by Agassiz, Murray, and their 

 followers, concerning the origin of coral islands, that 

 those attacked may be pardoned if they regard him as 

 an apostle of the old belief. 



Coming from the pen of Prof. Heilprin, this volume 

 will, however, be welcomed by both sides in the con- 

 troversy, but he must expect from his opponents an 

 energetic reply to some of his criticisms, and an unmis- 

 takable dissent from some of his conclusions. Thus 

 when the author asserts that the existence of an atoll in 

 the present position of the Bermudas is not demonstrable, 

 and that we have yet to learn to what form of coral 

 structure these islands belong, he is at variance with 

 most other authorities on the subject ; and it becomes at 

 the same time a little difficult to follow him in his conclu- 

 sion that the results of his researches go to sustain the 

 atoll-theory of Darwin, However, laying this difficulty 

 aside, and accepting the fact, fairly established in this 

 volume, that these islands have undergone recent move- 

 ments, first of upheaval and then of subsidence, we may 

 ask : " Of what use is this double testimony to any theory, 

 whether of upheaval or of subsidence, unless a direct 

 connection is first established between the form of a reef 

 and the character of the movement?" The direct testi- 

 mony of a single atoll that can be proved to have grown 

 in a stationary area will, unless this connection be estab- 

 lished, far outweigh the presumptive evidence derived 

 from a slight subsidence of every atoll in the Indian and 

 Pacific Oceans. 



Dr. Rein, in the instance of the Bermudas, was the 

 leader of one of the early skirmishes in this controversy, 

 and it was to his description of these islands that the 

 opponents of the atoll-theory of Darwin pointed in sup- | 

 Vol. XLi. — No. 1053. 



port of their views. They miss, therefore, in this book, 

 any special exposition on the author's part of the relation 

 of his own views to those of Dr. Rein. They also will 

 fail to see how Murray's explanation of the origin of the 

 inner basins of the Bermudas by solution can be met 

 merely by a statement of contrary conviction unsupported 

 by experimental proof. Nor will they agree with Prof. 

 Heilprin's assertion that the recent memoir of Agassiz on 

 the Hawaiian Islands can scarcely be said to contribute 

 materially towards the solving of the problem. 



The author in this volume treats as absurd my attempt 

 to show that a true conception of the relative dimensions 

 of an atoll is necessary to understand the nature of the 

 problem. I was aware that, if my meaning was not under- 

 stood, I should lay myself open to some curious reflec- 

 tions, and therefore the point is further elucidated in my 

 description of the Keeling Islands, in the Scottish 

 Geographical Magazine. To Prof. Heilprin's inquiry as 

 to how near are we brought to an understanding of the 

 character of an atoll by a true conception of its relative 

 dimensions, I would answer with the query, " How far are 

 we misled from the truth by the woefully-distorted sections 

 of atolls that are employed by lecturers and by the authors 

 of text-books?" Let me cite a single instance — that of 

 Darwin's section of the Great Chagos Bank, whichgives that 

 atoll (which is 76 miles in width and 40 to 50 fathoms deep) 

 the relative dimensions of a soup-plate. Some go further, 

 and draw, with a free hand, a deep, saucer-shaped section 

 of such reefs. Illustrations of this kind practically beg 

 the question at the start, if we are arguing in favour of 

 the theory of subsidence. The mind is at once informed 

 by the eye that there is a deep basin to be accounted for, 

 whereas a section on a true scale would exhibit no 

 appreciable depression. In the exaggeration of the rela- 

 tive depth of an atoll is concerned the very essence of the 

 problem, and a side-note cannot remove the impression 

 made by a false section on the mind. Our conception of 

 the problem can scarcely be assisted by a section of an 

 atoll representing in the lagoon greater oceanic depths 

 than the Challetiger ever plumbed. 



Passing from these controversial matters to the zoo- 

 logical section of this volume, we find a very interesting 

 chapter on the relationship of the Bermudian fauna. The 

 number of known species of marine Mollusca has been 

 increased from 80 to about 170, none of the eleven spe- 

 cies peculiar to Bermuda having been described before 

 this exploration. Strangely enough, though " over- 

 whelmingly Antillean in character," the marine Mollusca 

 include a Pacific element. The land mollusks have been 

 increased from about twenty to thirty species, of which 

 eight appear to be confined to these islands ; but, in 

 explaining the mode of transport of the non-peculiar 

 species, the author scarcely seems to have laid sufficient 

 importance on the transporting agencies of commerce. A 

 remarkable fact noted in connection with the Bermudian 

 crustaceans is the occurrence of three macrurans — 

 Palcemonella tenuipes, Palccinon affinis, and Penceus 

 velutinus— hitherto only recorded from the Pacific, Prof, 

 Heilprin arrives at some interesting conclusions in this 

 chapter, and perhaps the most important one is con- 

 nected with the large proportion of peculiar forms 

 amongst the land-shells, a circumstance which is pointed 

 to as evidence not only of the antiquity of a portion of 



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