HARDWICKE'S SCIENCE-GOSSIP. 



19 



observations on his interesting find, by a few notes. 

 Specimens in this genus devoid of fruit may be 

 roughly separated into two classes : i.e. those easy to 

 name, and those very difficult to name (without 

 fruit). Mr. Jackson's specimens belong to the latter. 

 Since I wrote to him I have received from the Rev. 

 Ottley specimens gathered in the river Soar, Leices- 

 tershire, that come about halfway between Mr. J.'s 

 and typical perfoliatus. And last year specimens 

 "near Mr. Jackson's" were gathered in the neigh- 

 bourhood of the Great Lakes in North America, by 

 my friend the Rev. T. Morong. I have not yet seen 

 these, but he writes me they much resemble the 

 Wetherly plant, of which ;I sent him a scrap and 

 drawing. He, like the finder and others, asks 

 " can they be abnormal prcelongus or perfoliatus ? " I 

 feel sure that when fruit is found it will prove to 

 come under perfoliatus as a variety, and it may well 

 bear the name given in the "Botanical Record Club 

 Report," by Dr. Lees, " P. perfoliatus, var. Jack- 

 sonV (name only). I need not say I shall be very 

 glad to receive many more such puzzles in the genus. 

 — Arthur Bennett, Croydon. 



Plants and the Snow-Line.— On some hills 

 there is a snow-line as on Slieve Snaght {Angliee the 

 Snow Mountain), Inisowen, co. Donegal. Has any 

 one else ever specially examined a hill with; this idea 

 in his head, to see if this snow-line could be traced 

 out by the plants ? This seems to have a connection 

 with the subject of Dr. Taylor's paper in "Nature." 

 It would be interesting to know if on such a hill the 

 plants are lower than on the neighbouring hills where 

 the snow only rarely lies. On Snaght the snow will 

 lie, while on neighbouring peaks higher than the 

 snow-line there will be none. — G. IT. K. 



GEOLOGY. 



The Drift - Beds of the North - West of 

 England and North Wales. — This is the title of a 

 paper just read before the Geological Society by Mr. 

 Mellard Reade, C.E., F.G.S. The author stated that 

 the first part of this paper, read in 1873, treated of the 

 low-level Boulder-clay and sands, specially in relation 

 to the contained shells. Since that time he has been 

 diligently collecting information to enable him to 

 treat of the nature, origin, and stratigraphy of the 

 Drift lying between Liverpool and St. Bees and 

 Liverpool and Carnarvonshire. He finds that, in 

 the basin of the River .Mersey, the Triassic rocks 

 underlying the low-level Boulder-clay and sands 

 are cut up by a system of preglacial valleys in some 

 cases, presenting very precipitous sides and not in all 

 cases following the present course of the rivers. If the 

 mantle of clay and sands could be stripped off, we 

 should have scenery differing considerably from the 

 present surface-features. These preglacial valleys are, 



in parts of their courses, considerably below the present 

 low-water level. Where the rock has been bared, and 

 it is of a nature capable of retaining striations, we 

 almost invariably find it planed and grooved in a direc- 

 tion approximately from north-west ; and when the 

 rock is soft, it is broken up into rubble and red sand. 

 Upon this debris of the Trias lie the low-level 

 Boulder-clay and sands of the plains, the clay lying 

 immediately on the rock being frequently, not 

 invariably, of a sandier and harder nature than the 

 upper beds. Lines of erosion of a local nature, but 

 often of considerable extent, often occur at the top 

 of this clay and then die out ; or there are thin or 

 thick beds of sand and gravel intercalated at the 

 junction and also dying out. Sometimes sand and 

 gravels underlie this harder clay ; but the larger mass 

 of the low-level clay is of a more plastic nature, and 

 is used in brickmaking. Intercalated sand-beds also 

 occur in this, and sometimes the clay gets stonier 

 again near the top. If we trace the drift from the 

 sea up each river-valley to the high lands, we see at 

 once that the nature of the clay gets more intimately 

 connected with the rocks in the basin above. This 

 is specially noticeable in the Ribble valley, where the 

 brown marine Boulder-clay gradually, above Milton 

 Bridge, gets replaced by a drift composed almost 

 wholly of the debris and grindings of the Carboni- 

 ferous limestone and grits above. In the mountain 

 districts, also, the drift becomes more localised, both 

 in Cumberland and Wales. The author's conclusions 

 are that an ice-sheet, radiating from the mountain- 

 district of the English lakes and the south of Scotland, 

 produced the planing and grooving of the rock and 

 the red sand and rubble debris ; then the ice melted 

 back into local glaciers, and the submergence began. 

 The low-level Boulder-clay and sands were, during 

 a slow submergence, laid down probably at depths of 

 from 200 to 300 feet ; and the author considers that 

 all the phenomena can be satisfactorily accounted for 

 by ordinary river-action and fraying of the coasts by 

 the sea, combined with frost and ice due to a severer 

 climate bringing down the materials of such river- 

 basins to the sea, while icebergs and coast-ice sailed 

 over, dropping on the sea-bottom their burdens of 

 erratic stones and other materials from the mountain 

 districts of the north. He pointed out, also, that the 

 great majority of the well-glaciated rocks were 

 specially those that could be traced to the highlands. 

 This fact was forced upon his notice after making a 

 large collection of glaciated boulders and pebbles. 

 Among the rocks he had been able to identify, with 

 the help of Professor Bonney and Mr. P. Dudgeon, 

 of Dumfries, Scawfell granite (Eskdale, of Mackintosh) 

 was the most abundant granite ; then came great 

 granites from Dumfries ; ^syenite from Buttermere, 

 which occurred all over the area described, and up to 

 1200 feet on the Macclesfield Hills, and syenite from 

 Carrock-fell. Other probable identifications were 

 also named. The whole series of rocks from the 



