September 17, 1891] 



NA TURE 



481 



and Devon. The Silurian rests transgress! vely on Ordovician 

 and pre-Cambrian rocks in Pembrokeshire, but is covered by 

 a continuous series up into the Old Red Sandstone and Car- 

 boniferous ; similarly the Morte Slates, which the author re- 

 gards as the oldest rocks of North Devon, and in which he 

 has recently found Lingulella Davisii, are covered by the 

 Devonian and Culm series of rocks. Mr. Ussher described the 

 occurrence of a volcanic series in the Lower Devonian rocks of 

 Tor Cross, and traced similar diabasic rocks amongst the 

 chloritic series of Pravvle Point, the excessive alteration of these 

 rocks being due to the greater nearness to the old resisting 

 rocks of the Channel. In this conclusion he was supported by 

 Mr. Hunt, who described the occurrence of detrital tourmaline 

 in the Devonian cliffs at the north-east end of Straiton Sands, 

 and compared it with the occurrence of similar material in a 

 quartz-schist west of the Start Lighthouse. Both schists and 

 sandstone contain detrital tourmaline, mica, fine-grained quartz, 

 and iron. 



Several palseontological papers were contributed. Mr. 

 Montagu Browne exhibited teeth, scales, and bones of Colo- 

 bodus from Aust, Watchet, and Leicestershire, which seemed 

 to indicate the identity of Colobodus with Lepidotus, and 

 possibly of Heterolepidotus with Eugnathus, and to give Colo- 

 bodus an extended upward range. Mr. Buckman gave an 

 account of the Ammonite zones in the Inferior Oolite. There is 

 a marked break on the Continent between the MurchisoiicB and 

 the Sowerbyi zones, which appears to be filled up by the zone of 

 Lioceras concavum in England. The So-cverbyi zone, however, 

 is absent in England from all localities except Dundry, and 

 Coombe near Sherborne ; and the author therefore sought and 

 obtained a grant to open an old quarry at the latter locality, in 

 order to fully investigate the fauna of the Smverbyi zone, and its 

 relationship to the concavum and Sauzei zones. Mr. Storrie, 

 of the Cardiff Museum, exhibited a fine series of slides and 

 drawings of Pachytheca and Netnatophycus, and gave a minute 

 description of them ; this elicited some discussion, in the course 

 of which Mr. Murray suggested that the former might possibly 

 be the egg of a Crustacean or some other small organic body 

 completely incrusted by a NuUipore. Mr. Smith Woodward 

 exhibited Pterodactyl and Plesiosaur bones from Brazil, and 

 gave an account of a series of Miocene fish-remains from Sar- 

 dinia. Other palseontological papers were one containing a 

 record of the occurrence of a variety of Estheria inimita in the 

 Lower Keuper building-stone of Chester, by Mr. De Ranee, 

 and one by Mr. Vine on the Bryozoa of the Upper Chalk. Mr. 

 B. Thompson gave an exhaustive report of the transition bed 

 between the Middle and Upper Lias in Northamptonshire, from 

 which he had obtained a large and valuable series of fossils. Mr. 

 Newton described the occurrence of Ammonites jurensis in the 

 Northampton sands, near Northampton ; and Prof. Hoyes 

 Panton gave an account of a mastodon of very large size at 

 Highgate, Ontario, and a mammoth from Shelburne, in the 

 same province. 



The occurrence of a strip of Lower Greensand four to five 

 miles long between Shaftesbury and Child Okeford, and running 

 parallel to the valley of the Stour, was described by Mr. Jukes 

 Browne. The same author attempted to explain monoclinal 

 flexure by the recurrence of movement in rocks already faulted, 

 but covered subsequently by unconformable strata ; movement 

 along the faults of the older series, under the influence of new 

 pressure, would throw the overlying series into monoclinal folds 

 or faults. The existence of a large area of Kellaways rock, 

 near Bedford, and the extension of Fuller's-earth works at 

 Woburn were commented on by Mr. Cameron. 



Several of the Committees appointed last year had done good 

 work. The Photograph Committee had obtained over 250 new 

 photographs of geological interest, many of which were exhibited 

 in the Section-room or at one of the soirees, where also Prof. 

 Wright displayed a fine series of transparencies illustrating the 

 lava and glacial deposits of the United States, and Mr. Stirrup 

 a set of slides of the dolomite district of Languedoc. The 

 Earth-Tremor Committee had been testing a number of record- 

 ing-instruments ; Mr. Smith Woodward reported that the lists 

 of type specimens were progressing, and that many large 

 Museums were publishing their own lists of types; Mr. De 

 Ranee gave an account of a number of wells in Yorkshire, Lin- 

 colnshire, Notts, Cheshire, Shropshire, and Glamorganshire ; 

 and Mr. Johnston-Lavis sent a description of the Vesuvian 

 eruption of 1890-91, the chief part of which has already 

 appeared in the columns of Naturf. 



NO. I 142, VOL. 44] 



BIOLOGY AT THE BRITISH ASSOCIATION. 



'TTHE papers read at this Section were fully as interesting, 

 •^ though not quite so numerous, as usual. A good deal of 

 time on one day was occupied by a discussion upon animals and 

 plants ; but as several of those who took part in the discussion 

 did not wish their remarks to be reported, it has been thought 

 better to leave out this part of the proceedings of Sec- 

 tion D. Botanical papers preponderated over zoological, 

 but it was not found necessary to divide the Section into two 

 sub-Sections. 



Mr. Grenfell read a paper upon the stmctare of Diatoms, 

 describing pseudopodia in these organisms. The pseudopodia 

 are quite easy to see in such a form as Melosira with even a 

 comparatively low power. They are very long and stiff, 

 radiating outwards from the periphery, and are apparently 

 non-retractile (they were watched for an hour without any 

 movements being observed) ; the pseudopodia are sometimes 

 nine times the length of the diameter of the Diatom, and are 

 occasionally branched ; adjacent Diatoms were sometimes seen 

 to be connected by a fusion of their pseudopodia. It was 

 suggested that the use of the pseudopodia is to keep the plants 

 floating, and to act as a protective chevcux de frise against their 

 enemies. These Diatoms were compared to Heliozoa, with 

 which they have evidently not a little resemblance in the form 

 of the pseudopodia. Incidentally Mr. Grenfell stated that he 

 had found a coating of cellulose upon the green corpuscles of 

 Archerina, which were regarded by Lankester as chlorophyll 

 bodies, and not as symbiotic algae. 



Mr. Wager described the presence of nuclei in Bacteria ; they 

 were met with in a species of Bacillus found in water containing 

 decaying Spirogyra. 



Dr. Gilson read a paper upon the nephridia of the leech, 

 Nephelis. The ciliated funnels appear to lose their connection 

 with the rest of the nephridium, and to perform the function of 

 organs for the propulsion of the blood along the channels in 

 which they lie. 



The Plymouth Zoological Station sent a record of work done 

 during the last year by the Director and by Mr. Cunningham. 



Mr. Calderwood read a paper upon some economical investi- 

 gations which had been carried out. He stated that three 

 investigations had been started within the present year, which it 

 was hoped would prove of great value to the fishing population 

 of this country. One was an attempt to produce an artificial 

 bait for use in long line fishing. This investigation was being 

 carried on by a competent chemist, and a considerable advance 

 had already been made towards a satisfactory solution of this 

 difficult problem. Inquiries were also being conducted with 

 regard to the occurrence of anchovies on the south-west coast of 

 England, and Mr. Cunningham, the Naturalist of the Associa- 

 tion, had carried out some inquiries at fishing stations on the 

 south coast. At present no net small enough in the mesh to 

 capture anchovies was employed, but that fish appeared so often 

 when the ordinary pilchard nets became entangled, as to suggest 

 that they might be present in considerable quantities. Anchovy 

 nets had, therefore, been constructed, and would be used during 

 the pilchard season this autumn. An investigation was also 

 being carried on into the condition of the North Sea fisheries, 

 which were declared to be rapidly declining. It was proposed 

 to draw up a history of the North Sea trawling grounds, com- 

 paring their present condition with their condition some twenty 

 or thirty years ago, when comparatively few boats were at 

 work ; to continue, verify, and extend observations as to the 

 average sizes at which prime fish, such as soles, turbot, and 

 brill, become sexually mature, and to collect statistics as to the 

 sizes of all fish captured in the vicinity of the Dogger Bank and 

 the region lying to the eastward, so that the number of imma- 

 ture fish annually captured may be estimated. Also to make 

 experiments with beam trawl nets of various meshes with a view 

 to determine the relation, if any, between the size of mesh and 

 the size of fish taken. Mr. Calderwood added that a regular 

 survey of the English Channel had been commenced, not only in 

 the deep water, but in various estuaries. A meteorological 

 station of the second order had been recently established, where 

 observations at 9 a.m. and 9 p.m. would be taken daily by wet 

 and dry bulb thermometers, barometers, rain-gauges, and sun- 

 shine-recorders. 



Mr. J. T. Cunningham read a paper upon the reproduction 

 of the pilchard. The ovum of this fish, described as such in 

 the Journal of the Association for 1889, w.is stated by Pouchet 



