268 



KNOWLEDGE. 



[Decembeb 1, 1898. 



and the dykes that cut this ferruginous zone can safely be 

 referred to the upper basaltic stage. 



This period of quiet must have been, indeed, a long one. 

 Lakes were formed, and forests grew, on the crumbling 

 surface of the earlier flows. Ked and brown nodular iron- 

 ores, like those still forming in the lakes of Sweden, are 

 quarried above Glenarm from between the lower and upper 

 lavas. Clay-beds, with numerous plant-remains, occur 

 here and in other places ; and bauxite, a sediment rich in 

 aluminium hydrate, forms a valuable ore of aluminium. 

 The pale colour of the bauxite, unlike that of the bauxite 

 of southern France, suggests that it was derived in this 

 case from volcanic rocks rich in alumina but poor in iron ; 

 and a very suggestive conglomerate occurs in association 

 with it near (rlenarm. A stream of the quiet period seems 

 here to have washed down pebbles of white and decom- 

 posing rhyolite, a lava rich in silica, and far removed in 

 nature from the basalts. A centre of rhyolitic eruption 

 probably lay at no great distance ; and at Templepatrick 

 and Tardree, in the neighbourhood of Antrim town, we 

 have clear proofs of the invasion of rhyolite into the lower 

 basaltic series.* 



The eruption of dark basicmatter seems, indeed, to have 

 been successfully interrupted, and the contents of another 

 reservoir of molten rock penetrated locally through the 

 the surface. In writing of the ]\Iourne Mountains,! we 

 have shown how the granite in that area is probably of 

 Cainozoic age, and how it truncates one series of basic 

 dykes, and is itself cut by a second series. The rhyolites 

 of Antrim almost certainly belong to the same epoch, and 

 have a similar chemical composition. A few cones were 

 reared locally upon the devastated surface of the country, 

 and their white flanks and vitreous lavas must have 

 contrasted strangely with the earlier basalts, which were 

 now reddening and decaying all around them. Denudation, 

 however, made short work of these little cones, and their 

 relics were subsequently buried under the upper series of 

 the basalts. Their products now appear, thanks to later 

 weathering, in some force around Tardree, which is one of 

 the most interesting volcanic districts in the whole of the 

 British Isles. 



Though Sir A. Geikie regards the group of rocks here 

 exposed as entirely intrusive, the great variety of glassy 

 lavas that occur on the plateau of Sandy Braes seems to 

 indicate volcanic action at the surface. We have no need 

 to go to Lipari or to Hungary for specimens of red tluidal 

 rhyolites, or spherulitic pitchstone,or black perlitic obsidian. 

 While the main layer of obsidian has broken up into isolated 

 blocks, which are decomposing into yellow sand, a frag- 

 mental rock hard by, formed of pumiceous particles and 

 blocks of compact brown rhyolite, seems to be a true tuff, 

 and to indicate explosive action. Down at Ballypalidy, a 

 little to the east, rhyolitic fragments, as has often been 

 pointed out, occur in beds of iron-ore among the basalts ; 

 and the locality, like Glenarm, has become famous by the 

 abundance of associated plant-remains. 



These remains, preserved in the deposits of a period of 

 repose, are unfortunately all that we have to guide us as 

 to the age of the whole series of eruptions. Formerly, 

 the flora was regarded as Miocene, and the close resem- 

 blance between the sequence of volcanic phenomena in 

 Antrim and in Auvergne in the Miocene period makes 

 the suggestion tempting to the petrographer. But Mr. 

 Starkie Gardner, who has dealt with the whole evidence 



* See Sir A. G-eikie, work quoted. Vol. 11., p. 205 ; and G. Cole, 

 " Ehyolites of the County of Antrim," Set. Trans. K. Dublin Hoc, 

 Vol. Vl. (1896), p. 105, &f. 



t Knowledge, Vol. XXI., p. 123. 



from Ireland, Mull, and even further north, has decided in 

 favour of placing the leaf deposits as far back as the early 

 Eocene. The scenery of our district in Eocene times was 

 thus in strange contrast to that of the London and 

 Hampshire basins ; but the Cleveland Dyke, crossing 

 England beneath the surface, shows how nearly the peace 

 of eastern lands was threatened. 



When the upper basalts spread across the country, new 

 centres of eruption were set up, Intrusive masses pene- 

 trated all the earlier rocks, and came here and there to 

 the surface as volcanic necks. The one striking object 

 among the inland plateaux of County Antrim is the 

 huge mass of Slemish, one thousand four hundred and 

 thirty-seven feet above the sea, which forms so conspicuous 

 and strange a feature above the basaltic moorland. This 

 sheer ridge of rock is composed of dolerite, rising through 

 the earlier lavas ; and doubtless at one time a great cone 

 of volcanic material lay about it. At Carnmoney, near 

 Belfast, a far smaller neck breaks through the Mesozoic 

 strata, and another rises as a dome-shaped mass above the 

 romantic valley of Cushendall. At Carrick-a-rede, and at 

 other points upon the Causeway coast, necks full of "bombs 

 of basalt, with pieces of chalk and flint," point to more 

 violent phases of eruption. Though nothing like a true 

 cone or crater remains in the whole Irish area, disguised 

 though the details may be by the effects of denudation and 

 post-Eocene earth-movement, we cannot doubt the cumula- 

 tive evidence as to the volcanic origin of the landscape. 



We still must send our students to Auvergne — or to 

 Catalonia, if they prefer it — to see how a few puys may 

 deluge a whole land with lava. But the wonder with 

 which we look across our great moorlands of the north 

 will not be diminished by the comparison. The far blue 

 crag of Slemish, standing out In the clear highland air, 

 will only become associated for us with days stranger and 

 more distant than those in which St. Patrick pastured his 

 sheep beneath its wall. 



CHRISTMAS CUSTOMS OF SHAKESPEARE^S 

 GREENWOOD. 



By Geobge Morlet, 

 Author of " Leafy Warwickshire," etc. 



THE first signs of the approaching custom of ' ' keeping 

 Christmas " may be observed as early as the middle 

 of October in the parlour of many a rustic cot in 

 leafy Warwickshire. In the wide and warm ingle- 

 nook (and the ingle is still to be met with in sundry 

 cottages and farmsteads of this stationary greenwood) a 

 small pyramid of sawn log-wood may be seen standing to 

 dry, and in the middle of the room, or in a recess, the 

 great green or yellow marrow is suspended by gay-coloured 

 ribbons from a hook in the rafter — the recipient of many 

 admiring glances, and many wishes for a slice out of it 

 when it shall be served as a Christmas dish. 



As the stuffed chine of pork is, among the peasantry of 

 this greenwood, the customary sign observed at the 

 mothering, so the ribbon-decorated marrow is one of the 

 symbols of the Christmas custom. The marrow is grown 

 to a giant size (the larger the more honour to the grower, 

 and the more plentiful the feast), is hung up in the house- 

 parlour until the eve of the festival, and is then prepared 

 and stuffed. 



Another custom preparatory to the great feast of the 

 year is the gathering of crabs, and the stewing of them 

 for a winter dish. In this we have an ancient custom, 



* Sir A. Ueikie, work quoted, p. 277; see also ibid, p. 271. 



