FROM MALDON TO CHELMSFORD, AUOUS'l' 8tH, 1891. 20I 



of any important fault which points in this direction, 'j'he only one, 

 indeed, shown on the (Geological Map which may possibly continue 

 to exist in this locality is that which throws down the Chalk on its 

 northern side to a depth of about 40 yards at the Royal Naval 

 College, Creenwich. But even in the case of faults of much greater 

 size, it is in the highest degree rash to prolong them in any direction 

 without evidence of their existence. To illustrate this point I have 

 brought with me a map of a portion of the Yorkshire Coalfield, which 

 gives a fair notion of the average state of things there. It becomes 

 at once evident on glancing at this Yorkshire map that where faults 

 exist others range more or less parallel with them, and are crossed 

 by a second series having an average direction nearly at right angles 

 to that of the first-named group. The evidence afforded by a map 

 hke this is of special value on account of the absence of drift, the 

 greater facility of tracing faults at the surface (as compared with 

 Essex), owing to the interstratification of hard and soft beds, and to 

 the information obtainable from colliery plans. Yet it shows how 

 few faults preserve an independent existence for a distance of even 

 six or seven miles, most of them being stopped off by others crossing 

 them in a much shorter distance. And — to return to Essex— we 

 have no evidence of the continued existence of the Greenwich fault 

 north of the Thames, while the distance between Greenwich and 

 Danbury is about thirty miles, in a straight line. 



If, however, we turn our attention from faults to those folds in 

 the strata which Mr. Ualton has so thoroughly worked out in his 

 paper on " The Undulations of the Chalk in Essex" (Essf:x Nat., vol. 

 v., pp. 1 13-1 17), we may obtain, I think, some explanation of the 

 unusual height of Danbury and Tiptree Heath for this part of Essex. 

 It is well known that where beds are thrown into synclinal folds they 

 are usually better preserved than where they form anticlinal curves. 

 Outlying hills are, therefore, usually found where the strata lie in a 

 trough or basin, and consequently dip towards the centre of the hill, 

 not away from it. Now, if we draw a straight line along the axis of 

 Tiptree Heath, across Danbury, and prolong it in a south-westerly 

 direction, we find that it passes through, or close to, the equally 

 lofty Bagshot outliers of Stock, Billericay and Warley, each attaining 

 a height of more than 300 feet. Beyond Warley we soon reach the 

 broad flat of old river-gravel and alluvium which covers so much 

 ground north of the Thames. But if we prolong our line southward 

 of the Thames we find ourselves at Shooters' Hill (420 feet), the 



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