204 ST PAUL'S CATHEDRAL. 



Bovey Tracey and the surrounding district, to trace 

 every exhibition of Gravel, ascertaining its constituents 

 and the various heights of its occurrence above the 

 river. His notes are suggestive and of much interest, 

 but we give only one brief extract : * 



Beyond Bovey Tracey the rocks are bare ; but descending to the 

 river at Woolford Bridge, we found ledges of a Gravel terrace 

 fringing the valley at a height of about 25 feet above the river. 

 It contained largish blocks of rolled granite, no scratched pebbles, 

 and is about 4 to 6 feet thick. At one place it is overlaid by 

 imperfect loess and angular debris. 



To judge from one early morning's start, the little 

 band of geologists was indeed enthusiastic " Saturday 

 by rail to St Austell, at 3 A.M." 



An interchange of letters with Sir Charles Lyell 

 took place this year, in reference to the foundations of 

 St Paul's Cathedral. 



Sir C. Lyell to J. Prestwich. 



73 HARLEY STREET, LONDON, 12th June 1867. 



DEAR PRESTWICH, I have been requested by the Dean of St 

 Paul's to read a page in Wren's ' Parentalia ' (p. 285), in which 

 he mentions the strata or layers of earth one above another 

 through which they dug when they made the foundation of 

 St Paul's. 



It is said that the old church had stood on very close and hard 

 pot-earth, which was about six feet thick, but thinning to four 

 feet towards the south. Below this they found nothing but dry 

 sand ; and still lower, water and sand mixed with periwinkles and 

 other sea-shells. These were about the level of low-water mark. 

 They continued boring till they came to hard clay. In conclusion, 

 it is said, "by these shells it was evident the sea had been where 

 now the hill is on which St Paul's stands." 



1 Further notes have been printed in the Geological Magazine, Decade iv. 

 vol. v. p. 414. 



