TRANSACTIONS OF SECTION C. 671 



they have not (Kentish Town, Crossness, Richmond, Streatham, and Culford), and 

 it is in the latter (jroup too that the character of the beds leaves their age in doubt. 

 So far another must be added to these, as no fossil has yet been found in the old 

 rocks at Stutton. 



Of the above 10 deep borings in the London Basin (usiog that term in the 

 widest sense, as including the Chalk tract that everywhere surrounds tlie Tertiary 

 beds) we owe 9 to endeavours to get water from deep-seated i-ocks, and in addition 

 to these D we have several other deep borings, which though not carried through 

 to the base of the Secondary rocks, yet c'ive us much inforuiation concerning those 

 beds (at Ilolkliam, Norwich, Combs, Winkfield, London, Loughton, Chatham, and 

 Dover). In one case only, that of Dover, lias the work been done for the purpose 

 of exploration, but now, after a few years' interval, a second trial has been made at 

 Stutton. 



Now both of these borings were started for a much more definite object than 

 merely to prove the depth to older rocks, or the thickness of the Cretaceous and 

 Jurassic Series. There is one particular division of those older rocks that has a 

 distinct fascination for others than geologists. We, happily, are content to find 

 anything and to increase our knowledge in any direction, but naturally those who 

 are not geologists, as well as many uho are, like to find something of immediate 

 practical value. As already shown, we owe much knowledge of ihe underground 

 extension of formations to explorations for water ; it has now become the turn of 

 geologists to help those who would like to find that much less general, though 

 nearly as needful and certainly more valuable thing, coal. 



The first place to suggest itself to those geologists who had worked at this 

 question, as a good site for trial, was the neighbourhood of Dover, and for various 

 good reasons. The trial has been made, and successfully, several hundred feet 

 of Coal Measures having been found, without reaching their base, but with several 

 beds of workable coal. 



Beyond that neighbourhood, however, geologists are not in such accord, and 

 generally speaking, fairly good re.asons can be given both for and against the 

 selection of many tracts for trial, except in and near London, where no geologists 

 would recommend it, from the evidence in our hands. 



Let us then shortly review the evidence that we have on the underground 

 extension of the older rocks in South-Eastern PiUgland, Avith a view of considering 

 the question of the possibility of finding Coal Measures in any of the folds into 

 which those rocks have probably, nay almost certainly, been thrown. 



The area within which the borings that reach older rocks in the London Basin 

 is enclosed is an irregular pentagon, from near Dover, on the south-east, to 

 Richmond on the west, thence to Ware, thence to Culford on the north, thence to 

 Harwich, and thence southward to Dover, the greatest distance between any 

 borings beimg from Dover to Culford, about eighty-six miles. It is therefore over 

 a large tract, extending of course beyond the boundaries sketched above, that 

 we have good reason to infer that older rocks are within reasonable distance 

 of the surface, rarely as much as 1 ,G0O feet, and mostly a good deal less. 



We must now consider some evidence outside the tract hitherto dealt with. 

 Southward of the central and eastern parts of the London Basin we have evidence 

 that the Lower Cretaceous beds thicken greatly, from what is seen over their 

 broad outcrop between the North and South Downs. We know also, from the 

 Dover and Chatham borings, that the Upper and Middle Jurassic beds come in to 

 the south-east, whilst the Sub- Wealden Exploration, near Battle, proves that those 

 divisions thicken greatly southward, the latter not having been bottomed at the 

 depth of over ] ,900 feet, at that trial-boring. 



Westward, however, near Burford in Oxfordshire, and some miles northward 

 of the nearest part of the London Basin, Carboniferous rocks have been found at 

 the depth of about 1,180 feet, these being separated from tbe thick Jurassic beds 

 (including therein the Liassic and Rb;«tic) by perhaps 420 of Trias. They consist 

 of Coal Measures, which were pierced to the depth of about 2-30 feet. 



In and near Northampton, north-eastward of the last site, and still further 

 from the northern edge of the London Basin, the like occurs ; but the beds found 



