August 



1898] 



NATURE 



Z77 



may be obtained by applying to Mr. Lydekker, at The Lodge, 

 Harpenden, Herts. 



Monday and Tuesday, August 29 and 30.— The museum of 

 I he Royal College of Surgeons will be open to members of the 

 Congress on production of their ticket. An official of the museum 

 will be present to receive visitors. 



Tuesday, Wednesday and Thursday, August 30 and 31, and 

 September i.— Dredging expeditions at Plymouth with the 

 Director of the Marine Biological Laboratory, and at Port 

 i:rin, Isle of Man, under the direction of Prof. Herdman, 

 F.R.S. 



^^/^. —Visitors to either of these dredging expeditions should 

 give notice to the Secretaries in writing as early as possible. 



The gardens of the Zoological Society of London will be open 

 to members of the Congress on showing their tickets and writing 

 their names in the book at the gates every day, including 

 Sunday, from. Thursday, August 18, to Thursday, September i, 

 inclusive. 



The Committee of the Royal Societies' Club, St. James's 

 Street, S.W., will extend the privileges of honorary member- 

 ship to members of the Congress (not ladies) on presentation of 

 their cards of Congress membership, from August 18 to Sep- 

 tember I, inclusive. Members of the Congress making use of 

 the Club must enter their names in the visitors' book. 



The President and Council of the Linnean Society, Burlington 

 House, Piccadilly, will throw open their apartments to the 

 members of the Congress of Zoology from August 27 to Sep- 

 tember I, inclusive. 



The gardens of the Royal Zoological Society of Ireland will 

 be open to members of the Congress who visit Dublin on pre- 

 senting their cards of membership at the gate. 



A YORKSHIRE MOOR. 



"T^HE Yorkshire moor is high, ill-drained, peaty, and over- 

 -^ grown with heather. Moors of this type abound in 

 Scotland, and creep southward along the hills into Yorkshire 

 and Derbyshire, breaking up into smaller patches as the 

 elevation declines. In the south of England they become 

 rarer, though famous examples occur in Dartmoor and 

 Exmoor. In the north they may cover great stretches of 

 country. It used to be said that a man might walk from 

 Ilkley to Glasgow without ever leaving the heather. That 

 was never quite true, but even to-day it is not far from the 

 truth ; a man might walk nearly all the way on unenclosed 

 ground, mostly moorland. 



Neither peat nor heather is confined to high ground. 

 Peat often forms at sea-level, and may contain the remains 

 of sea-weed. In some places it is actually submerged by change 

 of sea-level, and the peasants go at low water and dig 

 through the sand to get it. Heather ranges from sea-level to 

 Alpine heights. 



Peat may form because there is no fall to carry off the water, 

 or because the soil, though high and sloping, is impermeable 

 to water. A few feet of stiff boulder-clay constitute such an 

 impermeable floor, and a great part of our Yorkshire moors 

 rests upon boulder-clay, which is attributed to ice-action, 

 because it is often packed with ice-scratched pebbles, some of 

 which have travelled far, and because the rock beneath, when 

 bared, exhibits similar scratches. 



The rocks beneath the boulder-clay of a Yorkshire moor are 

 chiefly sandstones and shales. Where the sandstones crop out, 

 they form tolerably bold escarpments with many fallen blocks, 

 such as we call " edges " in the north ; the shales make gentler 

 slopes. Both the surface-water and the spring-water of the 

 moors are pnire and soft ; they may be tinged with peat, but 

 they contain hardly any lime, potash, or other mineral substance 

 except iron-oxides. 



The wettest parts of the moor are called mosses (in some 

 parts of Scotland they are called flow-mosses) because the 

 Sphagnum-moss grows there in profusion. The Sphagnum- 

 swamps are an important feature of the moor, if only because 

 ihey form a great part of the peat. Not all the peat, however ; 

 some is entirely composed of heather and heath-like plants, 

 while now and then the hair-moss (Polytrichum) and certain 

 moorland lichens contribute their share, but the Sphagnum- 

 swamps play the leading part, especially in starting new growths 



1 A discourse given at the Royal Institution, February i3q8. By L. C. 

 Mi.-»11, F.R.S. 



of peat. If we walk carelessly over the moor, we now and 

 then step upon a bed of Sphagnum. We have hardly time to 

 notice its pale green tint and the rosy colour of the new growths 

 before all close observation is arrested by the cold trickle of 

 water into the boots. The practised rambler takes care to 

 keep out of the Sphagnum swamps altogether, knowing that he 

 may easily sink to the knees or further. Sphagnum sucks up 

 water like a sponge, and if you gather a handful, you will be 

 surprised to see how much water can be squeezed out of it. 

 This water abounds in microscopic life ; Amoebie and other 

 Rhizopods, Diatoms, Infusoria, Nematoids, Rotifers and the 

 like can be obtained in abundance by squeezing a little Sphag- 

 num fresh from the moors. ^ As the stems of Sphagnum grow 

 upwards, they die at the base, and form a brown mass, which 

 at length turns black, and in which the microscope reveals 

 characteristic structural details, years, perhaps centuries after 

 the tissues ceased to live. 



An old Sphagnum moss is sometimes a vast spongy accumu- 

 lation of peat and water, rising higher in the centre than on the 

 sides, and covered over by a thin living crust. The interior 



Fig. 



-Leafy branch of Sphagnum, magnified ; one leaf of ditto, furthei 

 magnified. 



may be half-liquid, and when the crust bursts after heavy 

 rain, the contents of a hillside-swamp now and then pours 

 forth in an inky flood, deluging whole parishes. In 1697 a 

 bog of 40 acres burst at Charleville, near Limerick. In 1745 a 

 bog burst in Lancashire, and speedily covered a space a mile 

 long and half a mile broad. A bog at Crowbill on the moors 

 near Keighley burst in 1824, and coloured the river with a peaty 

 stain as far as to the Humber. In December 1896, a bog of 

 200 acres burst at Rathmore near Killarney, and the effects were 

 seen ten miles off. Nine persons perished in one cottage. 



The soaking-up of water is essential to the growth of the 

 Sphagnum, which employs several different expedients for this 

 purpose. Its slender stems give off numerous leafy branches, 

 and also branches which are reduced to filaments. These last 

 turn downwards along the stem, which they may almost conceal 



It is interesting to note that the same abundance of .inimal life charac- 

 ;es the mosses of Spitzberf ' ' ' ' """ 



are found. (D. J. Scourfield, 



terises the mosses of Spitzbergen, where not a few of the very same species 

 ~ ■ ~ Non-marine Fauna of Spitzbergen," Prot. 



Zool. Soc, 1897.) 



NO. 1503, VOL. 58] 



