OS 



HARDWICKE'S SCIENCE-GOSSIP. 



equinox. As to the relations which these effects 

 have to temperature, it was found that the mean 

 temperature of Edinburgh fell to its lowest on the 

 11th of January, when it was 34*8°, and from this 

 point it may be assumed that meteorological con- 

 ditions commence which result in giving vegetation 

 a start. Another question of great interest is the 

 relation of the colour of flowers to their date of 

 flowering. Taking 909 species of British flora, 257 

 were found to have white flowers, 238 yellow, 144 

 red, 94 purple, 87 blue, the remainder being green 

 and other colours. Of the blue flowers, 16 per 

 cent, bloomed in April ; 14 per cent, of the white 

 flowers bloomed in that month, but only 9 per cent, 

 of the reds, the yellows being very close to the 

 latter. It thus appeared that the blues were far 

 ahead of the reds and yellows, the whites being 

 intermediate, and the purples and greens came in 

 between the blues and the reds. This indicates the 

 existence of some general law which arranges the 

 flowering of plants in the British flora according to 

 the colours in the spectrum. 



GEOLOGY. 



How Anglesey became an Island. — The above 

 is the title of a most interesting paper by Professor 

 A. C. Ramsay, E.R.S. The author described and 

 illustrated by sections drawn to scale the contours 

 of the island of Anglesey and the adjacent parts of 

 Carnarvonshire, and noticed that the whole island 

 may be regarded as a gritty undulating plain, the 

 higher parts of wiiich attain an average elevation of 

 from 200 to 300 feet above the sea-level. Similar 

 conditions are presented by the country for some 

 miles on the other side of the Straits, and in both 

 the general trend of the valleys is north-east and 

 south-west. The rock surfaces, when bare, show 

 glacial striae running generally in a direction 30° to 

 40° west of south. The Professor indicated that 

 the great upheavals of the crust of the earth form- 

 ing mountains took place long before the com- 

 mencement of the Glacial epoch, and that ordinary 

 agents of denudition had ample time for the forma- 

 tion in mountain regions of deep valleys, down 

 which, during the Glacial epoch, glaciers would take 

 their course. He noticed the evidence of this local 

 glaciatiou furnished by the striation of the Welsh 

 mountains, from which he inferred that these moun- 

 tains as a whole were not overridden by a great ice- 

 sheet coming from the north, and he described the 

 course of the glaciers flowing from the north-west 

 slopes of Snowdonia as being in the directions west- 

 north-west, and north. These glaciers, however, 

 did not reach the region now occupied by the Menai 

 Straits, but spread out in broad fans on the north- 

 western slopes of the hills now overlooking the 

 Straits, a fact indicated by the directions of the 



glacial stria? in these parts. Anglesey, therefore, 

 was not glaciated by ice-masses coming from Snow- 

 donia; and as the striations on that island point 

 directly towards the mountains of Cumberland, the 

 Professor inferred that these markings were pro- 

 duced by a great ice-flow coming from that region, 

 reinforced probably by ice-streams from the north 

 of Scotland, and which were large and powerful 

 enough to prevent the glaciers of Llauberis and 

 NautlTrancon from encroaching on the territory of 

 Anglesey. Professor Ramsay described the rocks 

 bordering the Straits as consisting of nearly hori- 

 zontal carboniferous strata, which, from appearaces, 

 must once have filled the whole of the region now 

 occupied by the Straits. He considered that the 

 softer shaly, sandy, and marly beds, remains of 

 some of which are still to be seen on the coast, 

 were swept away by the action of the great glacier 

 coming from the north-east, forming a valley now 

 occupied by the sea ; and in support of this view 

 he cited the valley of Malldraeth Marsh, running 

 across Anglesey, parallel to that of the Menai 

 Straits, about four miles to the north-west, which 

 a very slight change in conditions would convert 

 into a ford, differing from the Straits only in being 

 closed at the north-east end. 



On some Unicellular Alce Parasitic 

 within Silurian and Tertiary Corals, with 

 a Notice of their Presence in Calceola 

 sandalina and other Eossils.— -This was the title 

 of a paper recently read before the Geological 

 Society, by Prof. P. Martin Duncan, F.R.S. After 

 noticing the works of Quekett, Rose, Wedl, and 

 Kolliker, which refer to the existence of minute 

 parasitic borings in recent corals, recent shells, and 

 a few fossil mollusca, the author describes the ap- 

 pearance presented by a great system of branching 

 canals of about 0'003 millim. in diameter, in a 

 Thanmastnean from the Lower Cainozoic of Tas- 

 mania. He then proceeds to examine the corres- 

 ponding tubes in Gordophyllum pyramidale from the 

 Upper Silurian formation. In sections of that coral 

 one set of tubes runs far into the hard structure ; 

 these are straight, cylindrical, and contain the re- 

 mains of vegetable matter. Neither these tubes, 

 nor auy others of the same parasite, have a proper 

 wall : they are simply excavations, the filiform a!ga 

 replaciug the organic and calcareous matter ab- 

 stracted. In some places the dark carbonaceous 

 matter is absent, and the lumen of the tube is dis- 

 tinguishable by the ready passage of transmitted 

 light. Other tubes run parallel to the wall, and 

 enter by openings not larger than their common 

 calibre. But there are others which have a larger 

 diameter, and in which the cytioplasm appears to 

 have collected in masses resembling conidia ; and 

 where fossilization has destroyed much of the con- 

 tinuity of a tube, a series of dark and more or less 



