Autumn Equinox 2021 by Andy Harrison

Welsh Equinox: Kath Norgrove

The Autumnal or Fall Equinox occurs annually on 22^nd or 23^rd September when, after completing three quarters of its orbit, the Earth’s equatorial plane passes through the geometric centre of the sun’s disk.  Temporally opposite is the Spring or Vernal Equinox that occurs annually on 20^th March.  Equinox is derived from the Latin aequinoctium, from aequus (equal) and nox (genitive noctis) (night) and represents almost equal global day and nighttime durations.  As the name suggests, September’s Autumnal Equinox astronomically marks the first day of autumn.

This year’s Autumnal Equinox took place on Wednesday 22^nd September 2021.  The date coinciding with our latest holiday to Wales and having arrived at Porthmadog, Gwynedd.  Sunrise was around 7.02 am and the weather started mild and cloudy with a light breeze and wet on the ground from overnight rain.

After a quick breakfast at our hotel, we headed to Porthdinllaen, a promontory on the Llyn Peninsular north coast adjacent to the town of Morfa Nefyn. 

Here, we undertook a circular 3.5 mile walk from Morfa Nefyn around the coast following a trail from an old AA guidebook.  The walk starts at a National Trust carpark, in Morfa Nefyn, and follows a lane up to the former coastguard station, which today is the headquarters for the Nefyn Golf Club.  Missing National Trust car park entrance on our way, we ended up parking in a field adjacent to the golf club and started the walk from here.

Following the trail, we went through the Golf Club’s main gate and continued along a tarmac access road down towards the golf course.  At a green roofed shed, used for storage and maintenance, the trail turned southwest and headed across the golf course to an iron shed.  However, this the iron shed was no longer to be seen and all that remained was a sandstone gateway and hedgerow where the shed once stood.  Our route then continued roughly westwards across the golf course to steep cliffs falling to shingle beaches and dark rocky outcrops.  

When the walk was originally written it followed a path northward that descended to a shingle bay (Borth Wen) below.  The route then crossed the bay to ascend the steep cliffs on the far side and back up to the golf course.  However, we could not find the path and no path down into the bay.  Looking closer at the cliff edge it was apparent that the original path had succumbed to coastal erosion and landsliding since the walk was first written.  The landslide backscar and slip mass clearly visible along the cliff edge.  The missing iron shed, and path raised our suspicions that the trail had been penned a long time ago and the route had changed since.  Other walks in the guidebook seem to hint that it was originally written around 1975.

Abandoning the bay, we continued northwards along the cliff / golf course edge where Jarrow, Cats Ear, Bell Flowers, Common Ragwort, Gorse and some heather still flowered.  Westerly winds pushed the clouds inland and replaced them with clear blue skies that eventually permitted warm sunshine to appear.  Warm moist air from the sea was forced upwards as it hit land creating a line of cumulus clouds that aerially mirrored the coastline. 

Our walk continued northwards onto the Porthdinllaen promontory following steep rocky outcrops to our left leading down to the sea.  Before long we came to a straight cleft cut through the rocky beach below.  To our right and smack in the middle of the golf course fairway was a vast sinkhole, or crownhole, approximately 29m to 39m across.  The cleft in the rocky beach below lining up nicely with a hole in the sinkhole’s base.  

Later, a look at the British Geological Survey website revealed that the rocks we were walking over were Cambrian volcanics that included pillow basalts and tuffs.  Intruded into these rocks were short and straight, Ordovician, microgabbro dykes.  Once such dyke matched precisely the cleft we saw in the rocks and associated with the sinkhole.  The dyke having weathered and eroded beneath the golf course and leading to the sinkhole forming.  Further along the walk, the coastline had been dramatically reshaped where an historical dyke had eroded leading to a crown hole collapse and coastal erosion. 

Historically, the promontory was used as an iron age fort and all that remained was a low earth embankment stretching from east to west.  The old fort ramparts were a reminder that twelve months previously, for the Autumnal Equinox 2020, we had ascended Moel Famau and Foel Fenlli in the Clwydian Range in eastern North Wales.  Moel Famau is the tallest peak in the range, at 554m, and Foel Fenlli represents one of numerous Iron Age forts strung out along the ranges length.  Our recent Wales excursions suggest that the region was a magnet for Stone and Iron Age settlements, fortifications and burial places.

On reaching the promontory’s northern end, we came to Trwyn Porth Dillaen lookout station sitting high up on an exposure of Cambrian pillow basalts.  These rocks having formed from submarine eruptions on submerged volcanic flanks around 600 million years ago.  The molten lava surface instantly chilling as it contacted seawater resulting in the eruption effusing gently like toothpaste from a tube.  The result being rounded structures resembling pillows. Hence the name.

We sat and ate lunch on the Promontory’s northern end, on exposed basalt rocks close to the sea.  In the shallows up to five grey seals bobbed about and rose and sank below the waves.  One light coloured female seal made grunting sounds and rolled over slapping her flippers on the surface to show her dissatisfaction at a dark coloured male’s advances.  The seals stayed away from the deeper waters where the outgoing tides could be seen at surface.  On a nearby rock perched numerous Cormorants and Shags sunning themselves.  Some could be seen floating on the water below the rocks and raising their heads like marine serpents.  In the rocks and vegetation around us Meadow Pipits flitted about and tweeted.

After over an hour watching the seals, we headed south along the golf course / promontory eastern edge and down to Porth Dillaen.  A small cluster of buildings that historically formed a port with its own shipyards.  Today the local pub, Ty Coch Inn, does a bustling trade for beach goers looking for refreshments.  Back and north along the coastline from Porth Dillaen, was the newer location for the lifeguard station.  From Porth Dillaen, we followed a sandy and shingle beach eastwards to Morfa Nefyn and to the National Trust carpark, before stopping for an ice cream at Caffi Porthdinllaen and headeding back to the car.

Inland windy and cloudier conditions prevailed and hid the sun.  Leaving Morfa Nefyn, we headed east along the coast to Yr Eifl which comprises three hills – Garn For (444m), Tre’r Ceiri Hillfort (480m) and Garn Ganol (564m).  Through variable sunny and windy conditions, we ascended a circular route up to the summit of Tre’r Ceiri Hillfort.  This 2,000 year old structure being enclosed by stonewall ramparts and containing around 150 stone hut circles.  The cold and windy, exposed conditions made the hill fort feel like it would have been a tough place to live.

Now situated within a National Nature Reserve, Tre’r Ceiri Hillfort is one of the finest of its kind. The rocks forming the Yr Eifl hills are intruded Tre'r Ceiri Microgranite and Caergribin Rhyolite, no date for which is given.  The cold and blustery conditions on the Tre’r Ceiri Hillfort summit and the sun going down put us off wanting to return via Garn Ganol.  So, we returned to the car via the route we came.  From Tre’r Ceiri hill, the view around the surrounding landscape was spectacular and our Ordnance Survey map revealed many more iron age and stone age wonders to visit.

With the sun rapidly approaching the horizon and before heading back to Porthmadog, we ended our equinox 12 daylight hours on the beach at Criccieth.  South-westerly winds driving waves ashore and the sun putting on a colourful display as it set around 7.16 pm.  Under darkening skies, we headed back to Porthmadog and to find somewhere for dinner.