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trating his views by tlie analogies of other rivers and estuaries. He 

 therefore presumes that the deposit of Cropthorne may have been 

 coeval with that of the northern drift. After an explanation of the 

 theories hitherto proposed to account for the transport of large boul- 

 ders to distant points, the author states that the evidences in question 

 seem to him to be subversive of the diluvial hypothesis v/hich imagines 

 that the blocks vi^ere carried over the land, it being proved that here, 

 at least, they were accumulated w?ider the sea. He does not think we 

 have yet been furnished with a full explanation of any method by 

 which such blocks can have been transported to distances of 100 

 miles : for supposing them to have been derived from the shores 

 of Cumberland, and that they extended in a delta from thence, it 

 would appear that assuming the slightest degree of inclination, viz. 

 3°, — which could give adequate momentum to the ordinary power of 

 running water acting upon these loose materials, — the southern part 

 of the delta (even at a distance of 50 miles from Cumberland,) must, 

 as suggested by Mr. Lonsdale, have Iain at the vast depth of i 3,000 

 feet beneath the sea, in which case all Wales would have been equally 

 submerged ; though we have proof that the mountains of that country 

 Ijtad risen to a certain height previous to the accumulation of the 

 northern drift. It is further submitted that under the physical features 

 of the region when this drift was formed, i. e. when a great arm and 

 strait of the sea separated England from Wales, submarine currents 

 alone could not have been powerful enough to propel these large 

 blocks, though the question is one which ought to be more completely 

 disposed of by those versed in the laws of dynamics. Mr. Murchison 

 next takes into consideration the theory of the transport by ice. After 

 allusion to the views of Esmarck, De I'Arrivi^re, Haussman, &c., it is 

 shown that Mr. Lyell has thrown great additional light on this subject 

 by his observations on Sweden and the Alps, by which it really ap- 

 pears that under certain limitations "ice floes" may have been " verse 

 causae" in the transport of large blocks, depositing them under seas 

 and lakes at great distances from the source of their origin. In the 

 Salopian case, however, though it is possible such means may also 

 have been employed, there are many arguments which weaken the 

 application of the hypothesis, such as the rounded and worn exterior 

 of the boulders, and their diminution in size and quantity from north 

 to south. It might also be contended that we have no right to infer 

 the existence of a colder climate in our latitudes in those davs ; but this 

 objection does not appear unanswerable, since it might be replied, 

 that if at the period of the northern drift England, Ireland, and the 

 continent of Europe were united by a lofty chain of mountains, there 

 might have been a temperature sufficient to have formed annually 

 large bodies of ice on the shores of Cumberland. Passing however 

 from this difficult question of the method of transport, Mr. Murchison 

 states that the greatest of the anomalies hitherto presented by these 

 boulders is obviated, when we dispel from our minds the idea of their 

 having been carried over preexisting lands. Having once ascertained 

 that large distributions of them took place under the sea, the different 

 heights at which we now find them may, he supposes, be satisfactorily 



