Mr, Wetherell's Observations on a Well dug on Hampstead Heath. 133 



In the list appended to this notice are ten new species belonging to the 

 class Conchifera*, and several species of Microscopic foraminifera'f. In 

 Plate VIII. fig. 2. 2 a., are represented two curious fossils. One of them is 

 cylindrical, externally smooth, and shining, and is composed of dark brown 

 spar; radiating internally like the Belemnite. The other is quadrangular, 

 but with the angles rounded, and possesses internally the same structure as 

 the first. Both effervesce strongly with muriatic acid. They are considered 

 by Mr. J. De C. Sowerby to be remains of Pennatula. 



The shells procured from ''the rock" between the London and Plastic 

 clays, are as follows : Rostellaria lucida, Natica glaucinoides, a Nucula, Pano- 

 paa intermedia, Cardium nitens, Venus incrassata, and a few casts apparently 

 of the genus Pleurotoma. Lignite and scales of fishes also occurred. In 

 some parts of the rock, were layers of calcareous spar, the surface of which 

 was beautifully studded with crystals of pyrites. The bed contained a great 

 many rounded flint pebbles, some of which were in a decomposing state ; and 

 a few of the same pebbles were imbedded in the lower part of the London clay 

 at the depth of 230 feet. I believe it is not very usual to find a bed of sandstone 

 between the two clays, but from its contained fossils, as the Panopcea inter- 

 media, &c., there appears some analogy between it and the Bognor rock|. 



The plastic clay presented several varieties of colour, as red, grey, white, 

 and yellow, variously intermingled. I examined it very closely without find- 

 ing the slightest trace of organic remains. At the depth of 330 feet, the 

 workmen arrived at a bed of sand, of a green colour, containing small flint 

 pebbles, and at this part soft water was obtained, which gradually rose to 

 within 200 feet of the surface. A steam engine is about to be erected on 

 the spot, but whether an adequate supply of water will be obtained without 

 the necessity of boring into the chalk, remains doubtful. 



* Plate VIII. t Plate IX. 



{; In a paper by Mr. Richardson, (Geological Proceedings, vol. ii. p. 79,) much sand and green 

 earth are stated to occur in the London clay near Heme Bay ; and in Mr. Rofe's paper on the 

 plastic clay of Reading, a rock is described at the top of the plastic clay. See p. 128 et seq. of 

 this volume. I have also a specimen from Egham. 



