© Liverpool Geological Society
Registered Charity No: 500067
Hon. Excursions Sec.: Maggie
(Please note 2 e’s in maggiee)
Fieldwork Programme 2018-2019
Further details of these field visits will follow.
Maggie Williams (Hon. Excursions Sec.)
Each person attending field meetings does so on the understanding
that they attend at their own risk.
Liverpool Geological Society has Public Liability Insurance Cover for
field (and indoor) meetings, but Personal Accident cover and
Personal Liability cover remain the responsibility of participants.
Visitors who are not existing members of the Liverpool Geological
Society are welcome to attend field meetings but are asked to pay a
temporary membership charge of £2 for each field meeting that
Field excursion to Llandudno
Leader: Professor Peter Burgess (University of
Date: 29th June 2019
Due to unforseen circumstances this field excursion has
had to be cancelled
Field excursion to Garn Prys and Deganwy
Leader: Ray Humphries
Date: 30th June 2019
The day will be split into two sessions revisiting two
sites: Garn Prys and Deganwy. These sites were last
visited by LGS, Sunday 16th March 1986.
Start for session 1 Garn Prys: Meet at Pentrefoelas car
park (GR 874515) (turn left off A5 in centre of village). We
will then organize to share cars and leave at 10.30.
There are also public toilets here and a chocolate shop
with cafe. Garn Prys has limited parking and is about 10
minutes away. Estimated time in the field - 1hr 30
minutes. Strenuous 1km walk up a farm track - normal
clothing based on weather - footwear sturdy shoes,
hard hats optional.
Start for session 2 Deganwy: Meet at Conway Business
Centre car park (GR 796776) next to McDonalds and
close to the cinema opposite from Tesco. Toilets
available at various outlets. Start 2.00 sharing cars again
Estimated time in the field 1hr. Minimal walking – a few
hundred metres on public paths and a little bit of a
scramble at one point
The journey from Pentrefoelas to Deganwy is 25 miles.
Approximate journey time is 45 minutes. This allows
people to stop at various locations for lunch.
After Deganwy there is an opportunity for people to go
by themselves to see the limestone on the Great Orme,
Llandudno or visit anywhere else on their return
Outline for the day:
Garn Prys: This itinerary is based upon a paper 'Garn
Prys: a mid-Silurian canyon, feeder to the Denbigh Grits
of North Wales' Authors R. Cave; J.A.Evans; and S.D.G.
Campbell published in Geological Journal, Vol 27, 301-
Garn Prys (SH8862 4835) is a hill, 534m O.D. and 3.5km
SSE of Pentrefoelas. The hill comprises of
conglomerates, sandstones and mudstones deemed to
be part of an infilled submarine canyon of Wenlock age
(Silurian). The palaeocurrent was thought to flow north
towards the main scarp of the Denbigh Grits (5km to
northeast). Evidence for this is in the sedimentary
structures and the acid volcanic clasts from Snowdonia
(Llewellyn Group). The rocks are unconformable with
the surrounding Caradoc (Ordovician) sandstones.
There will also be an opportunity to use
cleavage/bedding as a way for determining wayup,
thus allowing a fold to be identified along with possible
Deganwy Quarries: These disused and small quarries
contain 35m of mainly sandstones with some pebbly
sections known as Conway Castle Grit (Hirnantian age)
resting on Deganwy mudstones. Beds dip steeply to SE
and their deposition is linked to the Hirnantian
glaciations when sea level was estimated to be lower
by more than 100m. The sediment was deposited by
deep water turbidity currents or near shore storm
deposits. You decide! You will have seen coarse pebbly
conglomerate at Garn Prys, here at Deganwy you will
see that the rounded coarse clasts are composed of a
friable mud while the coarser surrounding matrix
contains some marine fossils which are not collectable.
To confirm that you would like to take part, please
contact Maggie Williams email:
firstname.lastname@example.org or telephone: 07784 720
27th Jul -
Hazel Clark, Chris Hunt, Dave Williams: Iceland