Potes on the Lover Coal Measures 
betheen Bagillt and Holvtvell. 
BY A. O. WALKER, F.LS. 
Read March 21st, 1878. 
HE traveller to Holyhead will see on his left, between 
Queen’s Ferry and Mostyn Stations, a line of hills sloping 
down to the shore of the Dee with a higher range behind 
them: the latter is the carboniferous limestone range, known as 
Halkin Mountain; and the former, with which we have to do 
to-night, is mapped by the Geological Survey as partly coal- 
measures, and partly—in the rear from the Railway—as mill- 
stone grit. Up to the Dee Bank Smelting Works, about one 
mile beyond Bagillt Station, the slope of the hill is true 
coal-measures, as shown by numerous collieries on it; but 
close to this point, a fault running N. and S. (known locally as 
the “ Boot” fault) has thrown out the coal bearing strata, 
and no coal has been got from this point to the Englefield 
Colliery, a little beyond Holywell Station. 
Going inland from this point towards Holywell, the first 
section we get is some distance from the high road to the 
South, in a dingle below a farm called Garreg Lydan (Cerrig 
Liwydion on the Ordnance Map), where there is a quarry, in 
which beds of coarse-rippled micaceous sandstones, sometimes 
over 3 feet thick, and soft interbedded shales, occur. The | 
dip here is about 5° N.-E. No organic remains, except 
perhaps some imperfectly preserved plant remains, have been 
