166 
J. HOPKINSOX-LIST OF WORKS 
and many of them inimitably variegated with various Colours and 
Figures. The Plumb Pudding stone may also be called a native of 
this County. Many of this kind which are found here will weigh 
twenty or thirty pounds, and will bear as fine a polish as Glass, 
and far exceed in beauty all the Marble I ever saw. In many of 
their gravel pits are also found clear, transparent pebbles, generally 
not exceeding the size of chestnuts, and seldom less than a pea, 
but as clear as a drop of water, and extremely hard. These cut 
and polish as fine as a Diamond, and when set upon a good foil 
appear extremely brilliant, and are capable of being made into 
Bings, Buttons, and various other Toys.” 
In Mr. Whitaker’s list 58 works are enumerated, and in the 
following supplementary list the numbering of the memoirs is 
continued from that, bringing up the total to 136. To this 
number the county histories, and a few other works in which refer¬ 
ence is made to the geology of Hertfordshire, published before 
1874, have to be added. To these additions, given as an appendix, 
a different series of numbers is prefixed. 
1874. 
59. Fordham, H. G. Notes on the Structure sometimes de¬ 
veloped in Chalk. [Ashwell.] Quart. Journ. Geol. Soc. vol. xxx, 
p. 43. 
60. [Lobley, J. L.] Excursion to Hatfield. Proc. Geol. Assoc. 
vol. iii, No. 6, p. 240. 
61. Sixth Beport of the Commissioners appointed in 1868 to 
enquire into the best means of preventing the pollution of Bivers. 
The Domestic Water-supply of Great Britain. Folio. London. 
(Numerous references to Herts.) 
1875. 
62. Brett, Dr. A. T. Mineral Spring at Watford. Trans . 
Watford Nat. Hist. Soc. vol. i, part 2, p. 63. 
63. Fordham, H. G. On a Collection of Fossils from the Dpper 
Greensand of Morden, Cambridgeshire [also Ashwell, Herts]. Proc. 
Geol. Assoc, vol. iv, No. 2, p. 150. 
64. [Hopkixsox, J.] Excursion to Watford. Proc. Geol. Assoc. 
vol. iv. No. 5, p. 284. Field Meeting, 1st May, 1875. [Berry 
Wood.] Trans. Watford Nat. Hist. Soc. vol. i, part 3, p. xv (1876). 
65. Lobley, J. L. The Cretaceous Bocks of England. Trans. 
Watford Nat. Hist. Soc. vol. i, part 1, p. 1. 
66. Whitaker, W. Guide to the Geology of London and the 
Neighbourhood. {Geol. Surv.) 8vo. London. (Ed. 2, 1875 ; 
Ed. 3, 1880; Ed. 4, 1884.) 
1876. 
67. Barrois, Dr. C. Becherches sur le terrain cretace superieur 
de 1’Angleterre et de l’lrlande. (Herts, pp. 150-153.) 4to. Lisle. 
68. Cltjtterbttck, Bev. J. C. The Geology and Water Supply of 
the Neighbourhood of Watford. Trans. Watford Nat. Hist. Soc. 
vol. i, part 5, p. 125. 
