XXVni PROCEEDINGS OF THE 



pi'csent river- valleys being then formed and gravel being deposited. 

 The gravel beds of the higher levels might be seen to contain 

 pebbles from a great distance — Wales, Cumberland, and even Scot- 

 land. They were the high-pebble gravels of Professor Hughes. 

 It was improbable that they were here first formed in place as 

 pebbles, some at least being pebbles of far older age. After the 

 pebbles were deposited an emergence took place, and the land 

 became scooped out, and great valleys were formed. During a 

 period of submergence the glacial or Boulder-clay materials were 

 brought from the north, and here the Boulder-clay was seen to 

 have mixed up the gravel of high-pebbles and to have brought 

 with it other materials. After this period a partial emergence took 

 place, and after this emergence rain and rivers gave the present 

 contour to the country, forming the third or river-gravel period, so 

 that the district now presents the beds of high-pebble gravel, 

 boulder-clay and gravel, and low-pebble gravel. 



From Hertford Heath the route lay through the " "Walnut-tree 

 Walk," and in refreshing shade, for the day was hot and the sun 

 shone brightly, a halt was made for luncheon, after partaking of 

 which the party passed through Amwellbury, the romantic grounds 

 of the Eev. P. D. Barclay Bevan, by permission of the Misses 

 Bevan, and came upon the high road near the Amwell Hill lime- 

 kilns, where a few fossils were found, and some fine examples of 

 vertical " pipes," exposed at the sides of an extensive chalk-pit, 

 were specially noticed. 



Climbing one of the sides of the pit, Amwell Magna*' was 

 almost immediately reached, and the well-known spring which 

 rises here from the Chalk, affording the New River Company a 

 copious supply of water, was visited ; but the beauty of the spot — 

 the church above, the river flowing by, the finely- wooded hill-side, 

 and the ornamental water reflecting the varied scene — diverted 

 attention from the spring, and from the interest attaching to its 

 situation and origin. It is evidently a subterranean stream, flow- 

 ing for some distance in the Chalk towards the River Lea, then 

 passing under it and rising on the other side, and finding its way 

 to the surface close to the river under which it flows. 



The next point of interest was near the New River Head, on the 

 road from Ware to Hertford. Here a boring is in progress by the 

 Diamond Rock Boring Company to afford an additional supply of 

 water for the New River Company. On arriving at the scene of 

 operations, the party, by permission of the New Hiver Company, 

 and of Colonel Beaumont, R.E., Director of the Diamond Rock 

 Boring Company, had the opportunity of becoming acquainted 

 with the various methods of working adopted. The first operation 

 consists in sinking by means of compressed air, — men working 

 inside an iron cylinder into which air is pumped, which drives 

 out round the edges any water which may accumulate while the 

 materials are loosened inside, the cylinder being forced down 



* Or Great Am^yell, tlie EmmewcUe or Emma's Well of Domesday Book. 



