460 DR. H. HICKS ON MAMMOTH AND OTHER 



In the district directly north of Euston Square, in all the 

 geological maps hitherto published, London Clay is shown to reach 

 to the surface, but I am doubtful whether this is the case over all 

 that area, for it is quite possible to mistake the brown clay which 

 overlies the gravel, where it happens to be free from stones, for 

 weathered London Clay. Over some parts of this district northwards, 

 especially in the neighbourhood of Eegent's Park and in St. John's 

 "Wood, I have recognized this clay with ' race,' containing included 

 patches of gravel, in cuttings of several feet in depth. The presence 

 of the gravel-patches clearly proves that it is not London Clay, but a 

 redeposited clay derived mainly from the denudation of the London 

 Clay. This re- deposited clay can usually be differentiated from the 

 London Clay, not only because it frequently contaius 'race' and 

 patches of sand, and shows bluish streaks due to the percolation 

 of water saturated with carbonate of lime ; but also because of the 

 manner in which it crumbles, when dry, into irregular fragments. 

 London Clay, even when much weathered, still retains evidences of 

 lamination, and is easily split along well-defined lines. With the 

 re-made clay, on the other hand, unless near the base, where it is 

 usually more or less sandy, there is very little evidence of lamination. 

 The London Clay, excepting for a foot or two under the gravel 

 (where it was usually found to be of a brown colour on account of 

 decomposition by percolating waters), was of a dark bluish tint, and 

 varied but little in any of the excavations. 



The valley scooped out of the London Clay, nearly in a line with 

 Endsleigh Street, as shown in figs. 1 and 2, seems to cut across 

 Endsleigh Gardens in a northerly direction, evidently towards the 

 comparatively low ground between Euston Eoad and Old St. Pan eras 

 Church, where at one point in the Old St. Pancras Hoad tlie 

 present height is given as 57 feet only above O.D. against 75 in 

 the Euston Eoad, and 85 in Upper Bedford Place. It is, of course, 

 quite possible that the London Clay may reach almost or quite to 

 the surface immediately north of Euston Square, but even then it 

 will be seen that the inclination of the old valley must have been 

 in the direction indicated, for the floor of London Clay exposed 

 under the newer deposits reaches to a height of 68 feet in Upper 

 Bedford Place, that is, 9 feet higher than the present level of the 

 road-surface in Old St. Pancras Eoad. In an easterly direction, be- 

 tween Endsleigh Gardens and the Fleet Yalley, London Clay is shown 

 in the Geological Survey Map to reach to the surface at heights of 

 75 and 80 feet above O.D., and therefore the Endsleigh Valley must 

 have been separated here from the Fleet by an important ridge, 

 narrowing gradually towards the north. On the western side of 

 Endsleigh Gardens the evidence points to another depression 

 towards Gower Street, for a section exposed in Gower Place, beyond, 

 but in a line with, the section reproduced in fig. 2, showed an increase 

 in the thickness of the deposits. It also proved that beyond the 

 < made ground ' in fig. 1 the yellowish clay again covered the sand 

 and gravel. This valley also seems to run in a northerly direction. 



The nearest section to that in Gower Place which has yet been 



