IY. 
A RECORD OF WATER-LEVEL IN A DEEP CHALK WELL AT 
ODSEY GRANGE, ROYSTON, 1878 - 1888 . 
By H. George Fokdham, F.G.S. 
Read at Watford , 18 th March, 1890 . 
PLATES I and II. 
The record of water-level in the well at Odsey Grange, which 
I commenced in November, 1878, having come to an end on the 
1st of October, 1888, in consequence of my residence abroad, I pro¬ 
pose to give a resume of the results of my observations, in order to 
insure that the labour they have involved may not be entirely lost. 
Two years ago, in preparing for onr ‘ Transactions ’ the observa¬ 
tions of the late Mr. John Pearce of Barley,* I expressed the hope 
that at some future time I might be in a position to deal more in 
detail than then appeared possible with the interesting question of 
the underground water-level in the Chalk of North Herts. To do 
this with any thoroughness -a very long series of observations would 
be necessary. Unfortunately, my own record, upon which I at 
that time relied prospectively for such a long series, has come to an 
untimely conclusion, and, in consequence, I merely now record the 
results such as they are, without attempting any adequate dis¬ 
cussion of the subjects upon which they throw light. 
I am only aware of three localities within the area formed by 
the outcrop of the Upper and Middle Chalk in the North of Herts 
in which observations of the water-level in deep wells have ever 
been made, namely, Barley,—monthly observations by Mr. Pearce 
(January 1st, 1864, to October 1st, 1886); Odsey Grange,—daily 
(November 29th, 1878, to October 1st, 1888); and Therfield 
Bectory, where a monthly record was commenced by the Bev. J. G. 
Hale on January 1st, 1883, and, I am happy to say, is being con¬ 
tinued at the present time. 
These three wells stand upon a line nearly E. and \Y., a distance 
of about 2-J miles separating the most westerly well, that at Odsey, 
from Therfield; Barley being about 4^- miles further E. from the 
latter village. They are all sunk in the Chalk on its outcrop in 
the valley of the Cam, along which valley, at lower levels, a 
number of springs, rising from the outcrop of one of the lower beds 
of the Chalk (on the horizon of the Tottemhoe Limestone), feed the 
westerly branch of the Cam (or Bhee). (See Plate I.) 
The maps illustrating various papers in our ‘Transactions,’! as 
well as those given in the Introduction to the ‘Flora of Hert¬ 
fordshire,’ may be referred to for the relative and geological 
position of these wells. 
It will be seen that, while both Barley and Odsey are within the 
Cam Yalley, Therfield stands on the ridge dividing the Cam Valley 
* 1 Trans. Herts Nat. Hist. Soc.,’ Yol. Y, p. 20 . 
t Yol. I, p. 127 , and Vol. II, pp. 151 , 154 . 
