Geological Society of London. 189 
sidered to be the equivalent of the Oolitic Marl. He then pointed 
out near Burton-on-the- Water the intervention of some sandy lime- 
stones and carbonaceous clays between the Clypeus-grit and the 
Fuller’s Earth; he thought they might possibly represent beds 
found above the Clypeus-grit near Chipping Norton. The beds 
marked in the map 5/ g 7’, hitherto termed Northampton Sand, he 
said were well shown in the new railway-cutting at Hook Norton, 
and were capable of being split into several divisions, the two thin 
base-beds containing Ammonites leviusculus and corals; the next 
higher (series C) yielding a large fauna, amongst which were Rhyn- 
chonella spinosa, Trigonia signata, and a doubtful fragment of Am- 
monites Parkinson. ‘These, with a higher series of sandy, marly, 
and siliceous limestones, designated D and E, were proved to extend 
over the high lands to the 8.W. It was shown that at one end of a 
ridge called Otley Hill the beds © rested on the Upper Lias, whilst 
on the 8.W. flanks of the ridge the Clypeus-grit was to be seen also 
resting upon the Upper Lias. A road section near Over Norton, he 
said, showed beds similar in lithological character to C and D of 
Hook Norton, resting upon the Clypeus-grit and evidencing a fauna 
of a somewhat similar character. The author thought that the 
almost unfossiliferous series EH, which had been called the Chipping- 
Norton Limestone, might probably be found to be the equivalent 
in time of part of the Fuller’s Earth, or of some of those beds of the 
Inferior Bathonian of the Céte-d’Or described by M. Jules Martin. 
2. “ Results of Observations in 1882 on the Positions of Boulders 
relatively to the Underlying and Surrounding Ground, in North 
Wales and North-west Yorkshire; with Remarks on the Evidence 
they furnish of the Recency of the Close of the Glacial Period.” By 
D. Mackintosh, Esq., F.G.S. 
The author began by showing how boulders may be regarded as 
natural time-measurers by their protecting the rock-surface under- © 
neath from the action of rain, which, around the boulders, denudes 
the surface, especially on the leeward and windward sides, where 
hollows resulting from pluvio-torrential action may generally be 
seen. He then described and explained the origin of the different 
forms of supports under boulders which graduate from flat surfaces 
to pedestals of various forms, which he divided into appropriated 
(or preexisting), and those acquired through the boulders protecting 
the underlying rock from denudation. ‘The author then described 
the positions of boulders on the high and uninhabited Eglwyseg 
limestone plateau near Llangollen, where it is certain they had never 
been disturbed by man. There he found that the average vertical 
extent of denudation by piuvial action around the boulders, since 
their arrival, was not more than six inches. After endeavouring to 
account for the fractured and crushed condition of the rocks under 
these boulders by precipitation from floating ice, he gave an account 
of his discoveries on the high limestone plateau north-east of Clap- 
ham (Yorkshire), where there is a “ ghastly array” of many hundreds 
of large Silurian grit and slate boulders, nearly black in colour. 
From many facts and considerations the author endeavoured to 
