306 NATURAL SCIENCE [November 
deposit by the action of currents. In obtaining the data from the 
recent species attention has been especially paid to evidence of depth 
at which the particular species occurs most frequently, and where it 
attains its best development. 
The material on which these calculations are based cannot 
afford a complete comparison on account of the number of Gault 
forms which are quite unknown in recent deposits, but this not- 
withstanding, an approximation to the truth may perhaps be 
obtained. 
The noteworthy and important groups of foraminifera found in 
the Gault, and which are not exactly represented in our recent 
faunas are— — 
(1) The strongly costate Nodosariae ; 
(2) The complanate and limbate Frondiculariae ; 
(3) The sulcated and limbate Vaginulinae ; 
(4) The remarkably developed and attached Ramulinae, the 
allied genus Vitriwebbina ; 
(5) And the limbate, reticulate, and spinose Pulvinulinae. 
The comparatively large size and redundant growth of these 
forms indicates favourable conditions for development, in which a 
high bottom temperature and a sufficiency of calcareous material 
dissolved in the water would form important factors. Another 
possibly important condition was the accumulation of marine shells 
over which this part of the Benthos of the Gault Sea was able 
to wander, and amongst which it could shelter. In the case of the 
Ramulinae and Vitriwebbinae these curious recent organisms 
attached themselves to the shells of the mollusea. 
Although marked changes are observable in the character of the 
deposits forming the Gault series in Kent, where they consist of 
green-sands, clays, and marls, it is somewhat remarkable that the 
actual rhizopodal fauna does not greatly vary; and so far as one 
can judge from the results now before us, the depths were not 
subject to so much oscillation as the lithological character of the 
beds might at first sight seem to demand. They are all more or less 
comparable with deposits forming in the moderately deep seas of the 
present day : they are probably represented by the green, blue, and 
red muds and the green-sands for the Lower Gault ; and by the semi- 
pelagic or terrigeno-globigerinw ooze (the meeting ground of the 
terrigenous and the pelagic deposits) for the marls of the Upper Gault. 
In connection with the subject it may be remarked that some 
years ago Professor T. Rupert Jones stated, in a note on an annelid 
bed at Westwell Leacon (3) that his colleague, Professor W. Kitchin 
Parker, believed the Gault Sea to have been 100 fathoms. 
F. G. Hilton Price believes the Gault Sea not to have exceeded 
100 fathoms in depth, and probably much shallower (4). 
