part 1] SECTION AT WORMS HEATH. 11 



Unfortunately, I failed to get a good photograph of the section,, 

 and so, to make the description clearer, I have drawn a diagram- 

 section, as was done on the black-board when this paper was read. 

 The figure, of course, does not show any one particular pipe ; but, 

 to the best of my ability and recollection, it generalizes the infor- 

 mation given by the set of pipes. At the same time, it is not far 

 from being a representation of the clearest and most notable pipe 

 at the time of my visits. In the progress of excavation this has- 

 gone : the section is constantly changing. 



Sometimes the Clay- with- Flints seems to be several feet thick ; 

 but this is deceptive, and, owing to the section being cut through 

 the circumferential part of the pipe, perhaps a frequent source of 

 error in regard to the thickness of beds seen in pipes. 



It should be noted that in this section superposition is no test 

 of relative age. The pebble-beds and sand clearly belong to the 

 Blackheath Series : the underlying loam and clay are the same 

 as that irregular surface-layer which occurs over so large an area 

 of the Chalk-with-Flints, and, perhaps, is of no definite age. 



Some years ago, when visiting Worms Heath with Prof. E. W. 

 Skeats, we saw something that was new to me, in a pit at the top 

 of the sharp south-western slope of Nore Hill. The contents of 

 a small vertical pipe of Clay-with-Flints had been compacted 

 while the surrounding Chalk must have been loose, so that while 

 the latter had gone, the once-included material of the pipe had been 

 left, as a short column a yard or more in diameter. 



There have heen many pits in this southern part of the outlier 

 (Nore Hill), and a large one, apparentl} r abandoned lately, still 

 gives a good section, with Chalk shown in two places, in one of 

 which it goes up to a high level. There are also pits in the 

 western part, northward of the high road, and Chalk has been 

 touched here too. 



III. Eemaeks on the Blackheath Beds. 

 (a) London Basin. 



The pebble-beds of Worms Heath do not differ from those 

 occurring elsewhere. Practically they are composed only, so far 

 as pebbles are concerned, of thoroughly rolled flints, varying in size 

 from about that of a pea to a length of several inches, most of 

 a flat ovoid shape, with a smooth surface, though this is often 

 slightly interfered with by very shallow whitish indents, caused by 

 the pressure of one pebble on another. 



The only exception to flints (from the Chalk), so far as I know, 

 is the very rare occurrence of pebbles of alight-brownish quartzite : 

 as an illustration of this rarity, during a residence of about 

 twenty-two years in Croydon, in Avhich much time has been spent 

 on the pebble-beds, I have found only two of those pebbles (one 

 this year at Nore Hill), besides another on the surface below the 

 escarpment of the North Downs, and this showed signs of having 



