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



Between the London and plastic clays a hard rock, five feet thick, was 

 bored through. It abounded with green, siliceous particles ; and contained 

 numerous shells, disposed in layers, but the greater part were in a very 

 chalky, decomposing state. 



A list of the organic remains obtained in the London clay, is given at the 

 end of this paper; and on perusal it will be found to contain many fossils which 

 have been met with in distant localities of the same formation, as Sheppy, Bog- 

 nor, and Barton. 1 mention this as an important fact, but by no means as a 

 new discovery, since Mr. Parkinson states in a most able paper on the Strata 

 and Fossil Remains near London*, that at Kew and at Highgate Hill, fossils 

 had been found of the same description as those of Sheppy and Hampshire. 



In the Hampstead Well were obtained some interesting remains of the class 

 Radiaria. The portions of Asterias in my possession, consist of a considerable 

 number of ossiculae. The largest, being granulated, probably belonged to 

 the sides of the animal ; and some of the smaller, without granulations, to the 

 middle or inner part. The ossiculas were irregularly distributed on the surface, 

 and within a piece of clay, but by immersing the mass in water, I was enabled 

 to save the greater part. 



Of the genus Pentacrinites, I have remains of two species; one is evi- 

 dently described by Miller in his Crinoidea, as having been found by the 

 late Mr. James Sowerby, at White Conduit House, Islington, &c., and is 

 thus spoken of : 



" These columns much resemble in size and shape those of Pentacrinites basaltiformis, but have 

 the angles more rounded. From their exhibiting no marks of muscular corrugation at their ex- 

 terior surface, and the points being of uniform thickness, I apprehend the fragments before me to 

 have been full-grown columnar portions. I wave distinguishing it as a species, not having the 

 ireans of furnishing a specific character ; yet, should it prove such, I should propose for it the 

 name Pentacrinites subbasaltiformis." p. 140. 



I have a specimen of spatangus which is strongly marked, but very fragile, 

 and was found at the depth of 250 feet. The same species was also found at 

 the Highgate Archway ; and the late H. H. Goodhall, Esq., informed me he 

 had in his collection one from the London clay at Barton. 



It is worthy of notice, that on comparing Terebratula striatula obtained 

 from the well with specimens found in the chalk, there was no apparent 

 difference f. 



* Geological Transactions, 1st series, vol. i. 



t Though this fossil is abundant in the London clay at Sheppy, and in the excavations for the 

 Birmingham Railway, near Chalk Farm, yet it has been rarely found in the English chalk. Aug. 



1837. 



