CHAPTER XXXIX. 

 NORTHERN DRIFT (continued). 



On the position of the great Bowlders which characterise the Northern Drift, and 



on the method of their transport. 



THE northern drift, as distinguished by its materials and association with sea-shells 

 of existing species, having been described, it still remains to inquire into the positions 

 occupied by the great blocks or bowlders which form part of it, and to endeavour to 

 explain how they could have been transported to the spots where they now lie 1 . 



Though of very general occurrence throughout the tract between the Cumbrian 

 mountains and the parts of Shropshire, Staffordshire, and Worcestershire just described, 

 the large granitic blocks abound in certain localities only. Thus, their great number 

 on the hills near Preston and other parts of Lancashire, not far from the sources of 

 their origin, has been adverted to ; and the table land north-east of Liverpool may be 

 further cited as richly strewed with them, sometimes of considerable size. In Cheshire 

 they occur at intervals, but more as solitary bowlders than in heaps. In North Salop, 

 on the contrary, and the adjoining parts of Staffordshire, they are found both isolated 

 and in groups. On the northern face of Haughmond Hill and the north-western slopes 

 of the Wrekin they are numerous, particularly at the former locality ; while a few 

 stray individuals extend southwards, lying on or near the surface of the other alluvia 

 for a few miles south of Shrewsbury (Lyth Hill, Longden, Stapleton, &c). These may 

 be considered as short tassels prolonged from the edge of the fringe before described. 

 The greater heaps, however, are lodged in Staffordshire, particularly in the district 

 west of the Dudley and Wolverhampton coal-field. (See Map.) Large portions of the 

 surface of the New Red Sandstone, between Bridgnorth on the west and Wolver- 

 hampton and Himley on the east, are so studded with these blocks as to be well worthy 

 of a visit. In the tract extending from the hamlet of Trescot to the village of Trysull, 

 in the south-western part of Staffordshire, their quantity and occasionally gigantic 



1 Mr. Greenough has marked upon his map the occurrence of these granitic bowlders in several inland places, 

 nd Dr. Buckland has reasoned upon them in his Reliquiae Diluvianse. In certain districts where they were 

 very numerous, they are fast disappearing through the labours of the Macadamites. The formation of good 

 roads must, therefore, be admitted as a vera causa for their rapid disappearance in districts where other good 

 materials are wanting. 



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