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NATURE 



{April 22, 1 8 So 



Opbiolepis mirabilis 



In a review of Lyman's description of the Ophiurans of the 

 Challenger, which appeared in Nature, vol. xxi. p. 513, I was 

 much surprised to find a criticism relating to a remarkable 

 species which I described last year in the Proceedings of the 

 Linnean Society. 



The reviewer informs your readers that Ophiolepis mirabilis, 

 Tuncan, is a true Ophiopholis, having all the structures of the 

 genus, and that it is allied to O. aculeata. This simple state- 

 ment leaves the impression that I have made a mistake, and that 

 I am ignorant of a well-known form. I therefore extract the 

 following from the Proc. Linn. Soc, vol. xiv., Zool., p. 479, 

 1S79:— 



" Ophiolepis mirabilis. — This common species has the disk of 

 Ophiolepis as diagnosed by Midler and Troschel ; that is to say, 

 the scales, which are of good size, and the large radial shields 

 are environed by rows of small scales, as by belts. But the upper 

 aim-plates have also the supplementary rows of small scales 

 around them, and there are also large accessory side-pieces. 

 .Moreover, there are hooks on the side arm-plates. This mix- 

 ture of Ophiolepian and Ophiopholian characters is very inter- 

 esting, and this species, I consider, renders the abolition of 

 Ophiopholis as a genus inevitable." In fact the beautiful 

 Ophiuran is a synthetic type, and I prefer its teachings to 

 authoritative statements, P. Martin Duncan 



Hastings, April 9 



The Stone in the Nest of the Swallow 

 Your correspondent, P. P. C. Hoek (Leiden), will find the 

 information which he asks for under this heading (vol. xxi. p. 404) 

 in an article which appeared in the Zoologist for May, 1867, 

 entitled "An Inquiry into the Nature and Properties of the 

 Swallow Stone and Swallow's Herb," by J. E. Hartinc 



24, Lincoln's Inn Fields, London, W.C., April 14 



The Songs of Birds.— Mr. C. C. Starling asks to be 

 informed of any book or paper which treats upon the uiu ical 

 propertie; of the songs of bird';. 



Dew Claws. — A. N. asks if any correspondent familiar with 

 wild species of Cam's can tell him whether the rudimentary hind 

 toe is invariably ] resent, or, if not, in what proportion of indi- 

 viduals, and whether it has bony function with the metatar.-us? 



THE EASTER EXCURSION OF THE GEO- 

 LOGISTS' ASSOCIATION TO THE HAMP- 

 SHIRE COAST 1 

 THE head-quarters of the Association were fixed at 

 Bournemouth. A large number of members arrived 

 before Easter, and were able to explore the freshwater series 

 to the west of Bournemouth, which could not be visited on 

 the excursion. An excavation into the leaf-beds having 

 ■been opened a few days previously by Mr. Gardner, Prof. 

 Morris, Dr. Henry Woodward, Prof. Corfield, and Mr. 

 Birch, a number of fine leaves were obtained, and Dr. John 

 Evans, Prof. McKenna Hughes, Mr. Warrington Smyth. 

 Prof. Bonney, and many others, were enabled to see the 

 lea.es in situ and the method of work. 



On Easter Monday some fifty or sixty members 

 assembled, and the party proceeded to Boscombe. On 

 the way the director pointed out the position of the 

 Bournemouth scries in the eocene formation, and the chief 

 geological features of the coast. Far to the west could 

 be traced the cliffs whence had been obtained a rich 

 dicotyledonous flora, shed apparently from forest trees, 

 which clothed the hilly slopes of the right bank of the 

 eocene river. It is remarkable to notice in how many 

 respects this flora differs from those found nearer Bourne- 

 mouth, most notably so in the total absence of palms. 

 The, next mass of cliffs is almost unfossiliferous, and 

 from its confused bedding is now conjectured to present 

 a transverse section of the actual bed, silted up, of the 

 old eocene river. Between this and Bournemouth, for 

 nearly a mile, extends the eastern series of leaf- 

 beds, containing the remains of a more tropical flora, 

 derived, perhaps, from low-lying country on the let t 

 ' Director, J. Starkie Gardner, F.G.S. &c. 



bank of the old river. Among the palms, which 

 are abundant, can be recognised such genera as Phoenix, 

 Calamus, Iriartasa, Sabal, Sec, and among the ferns, 

 species scarcely differing from such magnificently tropi- 

 cal forms as Osmunda javanica, Chrysodium aureum, 

 Glcichmia dichotoma, Lygodium dichotomum, &c. Beyond 

 these cliffs, skirting the downs of nearly vertical chalk, are 

 the Lower Bagshot beds, in which the well-known leaf- 

 beds of Creech Barrow, and Alum and Studland Bays are 

 situated. A very small portion, however, of the fresh- 

 water Bournemouth series could be actually examined on 

 Monday, for the chief object in view was to investigate 

 the recently-discovered marine series, described for the 

 first time in the pages of the Journal of the Geological 

 Society less than twelve months ago. The passage from the 

 one series to the other w-as well seen, although from the 

 absence of slips and consequent inaccessibility of the beds, 

 few fossils could be obtained. The beds are mostly dark 

 sandy clays, highly charged with lignitic matter, and they 

 contain in places well-preserved fruits and teredo-bored 

 wood. The evidence of their marine origin is amply 

 demonstrated by the presence of casts of Bracklesham 

 mollusca, masses of oysters, bryozoa, and crustaceans. 

 Overlying them are the clean white sands, with flint 

 shingle beds, of the Boscombe sei'cs. These eocene 

 shingle beds, from the perfectly-rounded form of the 

 pebbles composing them, show the former prevalence of 

 heavy surf upon the old shore-line. In many cases the 

 condition of the silex is wholly or partially changed into 

 a soft, white, chalk-like mass, entirely free from carbonates 

 however, and much speculation was indulged in con- 

 cerning the nature of this change. The party having 

 been joined by Dr. Alman, president of thej Linnean 

 Society, and Mr. Pike, owner of the vast china-clay pits 

 near Wareham, the curious Honeycomb chines were 

 explored, and the zone of nipadites pointed out, crowded 

 in places with the empty husks of fruits which had 

 floated out to sea. At another point proteaceous leaves 

 and tubular borings of annelids, filled in with horizontally- 

 disposed lignitic matter, were noticed. On the way to 

 Hengistbury Head it became apparent that as the fresh- 

 water beds present a transverse section across a vast 

 river channel, so the marine beds present a similar section 

 through a great eocene beach which formerly sheltered a 

 stagnant lagoon. These towards the east are seen to be 

 composed of larger and larger shingle, whose well-rolled 

 appearance indicates the distance it must have travelled. 

 Attention was particularly called to the resemblance of 

 the Boscombe series to the so-called Upper Bagshots of 

 the London Basin. 



Arriving at the Headland, after skirting its base and 

 examining its remarkable geology, the party somewhat 

 rapidly made their way through the heather on the 

 summit, past the prehistoric double wall and ditch, and 

 across the Stour and Avon by ferry to Christchurch, 

 where Mr. George H. Birch gave a most interesting 

 historical sketch of the priory. 



The second day was devoted to the cliffs between 

 Mudiford and Hordwell. The main features of the coast 

 were well seen as the haze lifted. The sequence of the 

 beds from Hengistbury to Highcliffwas pointed out by 

 the director, and the Barton clays and sands, the Upper 

 Bagshots and Headon beds of Hordwell were examined, 

 and numerous fossils collected. During the short stay 

 for lunch Prof. Morris favoured the party with an address, 

 in which he clearly placed before them the data for the 

 correlation of these beds with those of the rest of Europe, 

 and sketched in eulogistic terms the work of those who have 

 made it possible to trace the history of their deposition. 

 The members reached Lymington in time to return to 

 London or Bournemouth by the 5.50 train. 



The excursion, which was unusually largely attended, 

 was keenly enjoyed, owing to the magnificent weather 

 and the beauty and interest of the country traversed. 



