RICHARDSON : THE LOWER OOLITIC ROCKS OF YORKSHIRE. 187 
]Mi\ Hemes, writing in the following year, that is, in 1906, 
found this theory " difficult to accept," and was inclined to think 
that deposit was made fairly regularly over the whole of this 
part of Yorkshire until the lower portion of the Striatulus -Shales. 
had been laid doA\ n ; but that then there w as movement along 
the Peak fault, and whilst deposit was continuous on the depressed 
side of the fault, in other parts some erosion contemporaneously 
proceeded. 'Then the Dogger was laid down during a general, 
but by no means uniform, subsidence. ^ 
In November, 1909, I gave a lecture to the Ashniolean 
Societ}^ of Oxfordshire, and a summary was published in the 
" Report " for the year (loc. cit., pp. 32-40). 
In February, 1910, Mr. S. S. Buckman pubhshed a paper 
on " Certain Jurassic (Lias-Oolite) Strata of South Dorset and 
their Correlation," in ^hich he forwarded matters by dating the 
Lingula-Bed portion of the Grey Beds as dumortierice-dispansi. 
This he did mainl}' on the evidence of some fragments of ammonites 
collected by me in situ, and it enabled him to state that the deposit 
from which they had come was equivalent in time to " the middle 
part of the Gloucestershire Cephalopod-Bed and with the lower 
100 feet of the Yeo^il Sands near Yeovil."- Additional specimens 
of ammonites w ould lead him to regard the whole of the Grey Beds 
as dispansi in date {vide Appendix II., p. 209). 
In May, 1910, Part III. of the Jubilee Volume {" Geology 
in the Field") of the Geologists' Association appeared, in which. 
there is an excellent article b}^ Mr. Robert S. Herries, entitled 
" East Yorkshire " {loc. cit., pp. 594-595). The closeness in the 
dates of publication of Mr. Buckman's and Mr. Herries' papers 
did not permit of a reference to the former in the latter, and Mr. 
Herries contents himseK with the remark that : — 
"These marine beds [in ^ the Yorkshire estuarine series] all 
correspond to different horizons of the Inferior Oolite of the south of 
England, so that when the Cornbrash is found succeeding the Estuarine 
beds apparently without a break, it is clear that the Bathonian if 
represented at all, must correspond with the Upper Estuarines or a 
part of it." 
(i.) On the lower and upper limits of the Lower Oolites in 
Yorkshire. — Generally, the dividing-line between the Lias and 
OoHtes in Yorkshire is very obvious, because, whilst the former 
1 Proc. Geol. Assoc., Vol. XIX., Pt. 10 (1906), pp. 420-423. 
2 Quart. Joum. Geol. Soc, Vol. LXVI. (1910), pp. 81-82. 
