’ 
CO 
133 
opened up. However, let us see what the other side of the tunnel 
has to show us. Emerging to the daylight we come to a most 
interesting section of Sands, and one which, owing to a recent 
discovery,* will perhaps tend as much as anything to throw light 
on a much disputed point in geology. The question is, to which 
formation do these Sands belong? “To the Oolitic,” say we of the 
West with William Smith and Charles Moore at our head. ‘To 
the Liassic,” say those of the East with Dr. Wright as their 
champion. Who then shall venture to decide between these 
doughty combatants? Let us see what the section has to tell us. 
We have then before us an embankment some 40ft. in depth, and 
consisting in descending order first of some four or five feet of soil, 
with Oolitic debris—the subaerial gravel, or wash, from the hill 
above; this is succeeded by some 30ft. of yellowish much-disturbed 
green micaceous sands, with interrupted bands of hard, compact, 
calcareous stone. The Sands become highly ferruginous at the 
base and rest on a bed of stone some 2ft. in thickuess ; Oolitic and 
ferruginous outside, and full of fossils in which the Cephalopoda 
predominate ; hence called the Cephalopoda bed. This is 
succeeded by bands of buff-coloured clay and stone, some 
19in. thick, resting on a 7in. highly ferruginous and nodular 
bed of rock, containing similar fossils to the top bed, with 
nodules of ironstone and Jelemnites. This last bed rests on 
light-blue clays, a continuation of the same clays in the lower or 
West end of the cutting. We are here in the presence of a series 
of those debatable beds, called junction beds, which make our 
neighbourhood so important in a geological point of view—beds 
which represent the dying out of one formation and the coming 
in of another, and which are consequently of especial interest 
in their lithological and their paleontological aspect. We 
* It is but right, however, to state that since this was written Mr. 
Etheridge has thrown considerable doubt upon what Mr. Moore, myself 
and others deemed an undoubted portion of the young shell of Rhynconella 
spinosa, —H, H, W. 
