262 



THE YOUNG NATURALIST. 



My readers will probably have noticed 

 that while the fossils of one series are of sub- 

 tropical origin, those of another are decidedly 

 Arctic in their character. Thus we have 

 two extremes, intense heat, and biting cold. 

 Now it must be remembered that man had 

 not made his appearance until after the 

 Drift, therefore these changes had been 

 going on anterior to the creation of mankind, 

 and are of such a character, that they must 

 have taken vast ages to complete. We have 

 distinct evidence that England and France 

 have been joined, for the formation on both 

 banks of the English Channel coincide. 

 By the system of erosion, or wearing away of 

 solid matter by the action of water, the sea 

 has gradually encroached upon the land, 

 progressing further and further, and even- 

 tually separating the two countries. Even 

 during the Roman Invasion we hear speak of 

 the Isle of Wight, and are not informed of 

 any alteration in the configuration of the 

 coast lines bordering the Channel, so that it 

 must have been over 1900 years ago much the 

 same as it is at present. So we see that the 

 wearing away of rocks is a very slow process, 

 and therefore vast ages have been consumed 

 in the deposition of the strata alone. 



Again, let us glance at the Miocene deposits. 

 We find that during this age palm and fig 

 trees, vines, cinnamon trees, and elephants, 

 actually nourished in this country ! A glance 

 at the Glacial Drift deposits will immediately 

 show that England's climate was then Arctic 

 in its temperature: for do we not find among 

 the clay, striated stones, or flattened blocks, 

 scored and grooved all along their surface. 

 In regions where glaciers abound, this scoring 

 of rocks is now going on, and is caused by 

 the passage of huge masses of ice over their 

 surface. This is all-sufficient proof that 

 mountains of ice have actually existed in 

 the British Isles, conveying with them these 

 scored boulders, and lodging them, together 

 with other matter, in the hollows where the 

 glacier has eventually become stationary. 

 Thus it is apparent that England's climate, 



which was once sub-tropical, has gradually 

 changed to one much colder. A vast amount 

 of time has indisputably been consumed in 

 these changes, during which many varieties 

 of life lived and flourished, with the chief 

 exception of man, showing that the changes 

 abcve enumerated have been proceeding 

 long, long before the appearance of the 

 human race. 



May we not indeed say with the immortal 

 poet, Shakespeare, " Sermons in stones, and 

 good in everything." But our geological 

 knowledge is far from being perfect. There 

 is much yet to be learnt by the aid of science, 

 and though rapid strides are being made 

 towards perfection, the cry ever on the lips 

 of the hosts of scientific warriors, is " Ex- 

 celsior ! excelsior ! higher, still higher ! " 



I will conclude this paper with a few notes 

 upon the collection and arrangement of fossil 

 remains. Fossils, like many insects, are 

 local. We must not look for 0. radiata in the 

 Chalk, nor A . uvatus in the Cambrian ; but 

 search for 0. radiata where the Cambrian 

 formation occurs, and A . ovatus in the chalk 

 cliffs of southern England. Fossil-hunting is 

 by no means as easy as insect collecting. 

 They have to be searched for in the solid 

 crust of the earth, and then laboriously 

 broken out of the stone with hammer and 

 chisel. 



Special hammers are made for geological 

 purposes. I have generally used one very 

 similar to those adopted by carpenters, hav- 

 ing one end flattened, like a chisel, and the 

 other broad and round. 



Great care must be taken in breaking out 

 the fossils. If the rock under examination 

 be stratified, or of a shaly composition, the 

 blow must not be delivered at right angles to 

 the plane ®f the layers, but in the same 

 straight line with them. In other words, 

 strike with the chisel-shaped extremity of the 

 hammer, the ends where the parallel strata 

 show themselves. 



In some cases it is very difficult to tell 

 which is the fossil, and which the impression. 



