HARDWICKE'S SCIENCE-GOSSIP. 



off, frozen into the great icy mass, and slowly carried 

 away. When that portion of the glacier into which 

 some huge fragment has thus been frozen, reaches the 

 sea, it would be broken off, and floated away as an 

 iceberg, carrying the enclosed fragment of rock with 

 it. Away drifts the iceberg, carried by oceanic 

 currents in a southerly direction, until the warmer 

 waters gradually melt it, and then down drops the 

 rock to the bottom of the sea, to rest perhaps thou- 

 sands of miles away from its parent source. 



The friction of a moving glacier elicits just 

 enough heat to melt a portion of the ice, which 

 flows away as water, carrying with it the finer mud 

 or sand set free by attrition. Hence all the water 

 flowing into the sea is turbid with mud, and this 

 mud, as it gradually settles to the sea-bottom, is 

 there forming what will some day be a geological 

 deposit. In this mud arctic mollusca live and die, 

 and will also some day be found fossilized. It was 

 in a similar bed to this that I was dropped. Down 

 I sank amid the oozy mud, displacing the strata, 

 and more or less causing them to assume a con- 

 torted appearance. Well do I remember the effect 

 produced by the largest boulders, dropped in a simi- 

 lar way into the same strata. They sank so deeply 

 as to cause thin beds of shells, which had previously 

 been horizontal, to wrap over and become almost 

 vertical. In the Norfolk cliffs, near Cromer, where 

 what is known as the "Coast Boulder Clay," 

 attains a great thickness, you may see masses of 

 chalk imbedded, which cannot be less than two 

 hundred feet in length. The soft sand and clay beds 

 near are so contorted that you would imagine an 

 earthquake had produced the disturbance ; but it 

 was caused simply by the melting icebergs drop- 

 ping their stony burdens. Por ages this process 

 went on — the land glaciers grinding down the solid 

 rocks, and the sea currents strewing the debris over 

 the ocean-floor. The icebergs, also, added no little 

 to the accumulating mass. 



I am told that along the North Atlantic sea-floor 

 there is going on a similar deposit. The thousands 

 of icebergs which set out from the north every 

 year gradually melt as they near the more southerly 

 latitudes. There is a great stream of warm water 

 called the " Gulf Stream," which sets out from the 

 Gulf of Mexico, crosses the Atlantic, aud impinges 

 on the southern and south-western coasts of Great 

 Britain. When the northern icebergs come into 

 contact with this, they rapidly melt, so that, of 

 course, the sea-bottom in that place might be ex- 

 pected to be heaped up with the debris they had 

 dropped. Actual soundings prove this to be the 

 case ; so that if the North Atlantic sea-floor could 

 be upheaved, you would have a series of loose 

 deposits of sand, mud, boulders, &c., not unlike 

 those which were formed during my own lifetime. 



I am not left without a natural barometer to fix 

 the depth to which the dry land went down. In 



North Wales is a hill called Moel Tryfaen, and, 

 near its summit, at seventeen hundred feet above 

 the sea-level, is an old sea-beach, formed when the 

 submergence had reached its maximum. After this 

 there came as gradual an upheaval, and this is 

 marked in various places in Great Britain by a 

 graduated series of raised beaches, ranging ia 

 height from that above given to those only a fsw* 

 feet above high- water mark. Gradually the land 

 appeared more extensively above the water. The 

 climate was still intensely cold and arctic. The 

 icebergs coming from Scandinavia frequently, 

 brought with them arctic plants growing on the~ 

 frozen mass of gravel or sand. Whenever these 

 icebergs stranded on the coast, these plants were 

 able to migrate inland, and very soon they covered 

 the new land with an arctic aud sub-arctic flora. 

 Those soft beds of sand or mud lying along the 

 sea-bottom which first came within the influence of. 

 the surface-currents, wei*e very much worn away 

 or denuded. This was especially the case with an 

 extensive sheet known as the "Chalky Boulder 

 Clay," from its containing so many small rounded . 

 pebbles of chalk, as well as large boulders of other 

 rocks. 



Among farmers, this goes by the name of " Heavy 

 lands," and the bed is usually found occupying the 

 highest grounds, having been denuded by marine 

 currents into what are now valleys. A good deaii 

 of the material thus worn away was carried by the 

 waves to form beds of later date, which sometimes 

 go by the name of " Post-glacial," although they 

 were really deposited during the Glacial epoch. Of 

 course, we boulders had no means by which we 

 could be transported, and so we were exposed to- 

 current-action. The waves rubbed us together, 

 toning down our sharp angles, and very frequently 

 obliterating the scratches and groovings which we 

 had before borne as evidence of our ice-conveyance. 

 In this way a huge gravel or boulder bed was 

 formed on the highest grounds, the soft matrix 

 having been washed away. 



When England was again joined to the Con- 

 tinent, and before the Straits of Dover had been, 

 cut out, the European land animals migrated hither. 

 The climate, though still rigorous, was nothing like 

 so cold as it had been during the middle of the 

 Glacial period. Among the animals thus roaming 

 amid semi-arctic woods and wilds, were the 

 "Mammoth" (Elephas primigenius) and the Hairy 

 Rhinoceros. Both these animals were covered 

 with long woolly hair to protect them from the 

 severe cold. Ireland was then joined to England. 

 by way of the Isle of Man, and over this extensive 

 prolongation of Europe in a westerly direction, 

 another animal, the " Irish Elk," roamed in great 

 numbers. The Reindeer, Glutton, Lemming, Musk- 

 deer, and other animals affecting high latitudes, 

 then abounded in England, their bones being fre- 



