74 John Gunn — Causes of Change of Climate. 



ice-scratclied boulders, in the Coal-measures ; but a mild and sub- 

 tropical climate seems to have prevailed. 



If we pass on to the Permian, the change both of Fauna and Flora 

 appears to be coincident with that of the level of the land. A great 

 and general disturbance took place, and glaciated and striated rocks 

 prove the reality of a Glacial period. This was first observed and 

 announced by Professor Eamsay. It was exposed in many places 

 to such an extent as to excite surprise that it had not been noticed 

 before. 



From that epoch, to and throughout the Oolitic, a gradual and 

 general levelling took place, and no striated boulders nor auj- in- 

 dication of ice-action have been discovered. 



If in the Chalk, as pointed out by Mr. Godwin-Austen in his 

 elaborate treatise ^ a mass of granitic rock has been found at Croydon 

 imbedded, it exhibits no more than the wasting of the land by floods, 

 or inroads of the sea, or it may have been carried, as he suggests, by 

 sea-coast ice from Polar regions, but such masses are rounded and 

 afford no proof of local glaciation. 



In no parts of this country, we might say of Europe, are there 

 equal facilities offered for observation, as in the eastern counties of 

 England, and this arises from the continuous and unbroken succession 

 of the strata : consequently the relations of cause and effect are very 

 minutely and extensively disclosed, and we cannot fail to see how 

 changes of climate and of the Fauna and Flora follow step by step 

 on the elevation or depression of the land. 



It can be demonstrated that throughout the Norwich Crag series, 

 and the Stony-bed, which dates from the surface of the Chalk, to the 

 present day, atid through the Forest-bed series, the Laminated series, 

 which includes the Chillesford clays and sands, and through the 

 Westleton beds, and the entire Quaternary formations commencing 

 with the lower Boulder-clay, and ending with the Post-Glacial 

 deposits, all the changes of climate and of fauna and flora have gone 

 pari passu with the changes of the level of the land. 



Thus the Mastodon arvernensis, whose remains are found in the 

 Bone-bed in Suffolk beneath the Ked Crag, and in the Stony-bed 

 beneath the Norwich Crag, occurs in certain Antwerp-beds at a 

 lower level than that in which the remains of Elephas meridionalis 

 are found. 



That Elephant succeeded the Mastodon arvernensis, and appears 

 in the Estuarine-bed of the Anglo-Belgian basin without the Masto- 

 don, which had ceased to exist in that district at least. 



A change of level then took place ; the Forest began to grow u])on 

 terra firma, and there was a concurrent change in animal life ; 

 the Elephas meridionalis either disappeared altogether, or else the 

 rugosity of the enamel-plates was so modified, and the number 

 increased, as to be scarcely recognizable. 



Another and distinct species, or rather form of Elephant appeared. 

 This was named by Dr. Falconer E. (EuelepJias) antiquus, and it is 

 supposed to have undergone many variations with respect to the 

 1 Quart. Journ. Geol. Soc. vol. xiv. p. 252. 



