Tremelecia atrata and Waxcaps on a walk along the (south) Craven Fault above Settle

 Did I tell you I had discovered lots of local Settle walks during Covid? well I learned a new footpath for me and new views today that I never found during Covid. 

And most important a new record of this metal loving lichen beyond the SE end of its main range in the North of England in The Lake District and Swaledale.

Tremolecia atrata

Where did I go?

(If you want to skip this geology detourt go straight here to the rock)

The narrow tarmac road Michell Lane that runs SE from Settle is  initially on the level at 190m above sea level. A footpath from Mitchell Lane runs from the road at 198m then up along a track beside the reservoir wood, and  parallel to the road. The rock of which the wall is made is gritstone/sandstone. The geology of the rocks here correlate / are an extension of my walk at Giggleswick

The Bedrock just here is Pendle Grit member, but the level above it and in some cases lateral to it is Brennand Grit.  (and in some cases lateral with it) is Brennand Grit.  (Click!  that must be why the reservoir was originally built here - gritstone is impermeable to water.)  How can you tell the difference between Pendle Grit and Brennand grit? - Field tips: if you see abundant rounded quartz pebbles and strong cross-beds, lean Brennand; if you see thick, massive, feldspathic beds with fewer pebbles and interbeds of silt/mud, lean Pendle. NERC Open Research Archive+1

This is a whitish lichen with black apothecia on the dark siliceous wall.
I am still thinking about this lichen.

Then the path turns ENE up through the field 

Two yellow waxcaps with yellow stipes in foreground

I climbs up a steep, steep slope to the top corner of the reservoir wood stillwith its regular gritstone  wall. At 258m. 

Ancient wall?

As I walked up this slope, I looked up and could see the wall running along the skyline SE from the wood wall was made of big boulders with the sky showing through between. Intriguing.  Was this an ancient wall?   Some of the walls in Ireland, made of much smaller stone, have the sky showing through like this and so do a few of the walls above Malham Tarn House.

  Or had the boulders been moved here recently (last 100 years) with the help of machinery as a way of clearing the field?  I discovered  the boulders I had been looking up to were supporting the soil of flat field above, they were a retaining wall - like a Ha-ha

The vegetation and soil on which the boulders are perched is "old vegetation" - i.e. heathland type - Polytrichum juniperinum and Heath grass (Danthonia decumbens) and Heath Bedstraw (Galium saxatile)

Apricot Clubs in the foreground.  Heath grass with upper surface of blade whitish so the two grooves down the centre of the blade show up.

Whereas the soil in the flat field above the boulder wall and also on the slope below starting 3m down the slope is softer-lusher-Yorkshire-Fog grass and Tufted Hair-grass and one or two rushes. (MG9 National Vegetation Classification Type)

 I initially thought this was due to improvement by muck spreading -but a search of the internet shows  there is glacial till (boulder clay:- clay and jumbled angular rocks of different sizes brought up here and deposited by the ice maybe 20,000-15000 years ago) on the ground above and below the wall, whereas the ridge where the boulders have been placed has no till. (according to Cuacera website) The bedrock is The Brennand Grit is "Very coarse, pebbly to medium-grained cross-bedded feldspathic sandstone with minor siltstone beds." I certainly noticed the pebbles in some of the rocks.

(The actual junction, the fault, between the Grit and the limestone is some 80m NE of here, across the flat field between us and Springfield Farm.)

What caught my eye was a completely different type of geology - the largest boulder in this boulder wall was a smooth siliceous rock - a glacial erratic - gleaming with patches of fluorescent green of the lichen Rhizocarpon geographicum - and contrasting with blue sky and white clouds behind.

Centre: Rhizocarpon geographicum  Right thick thallus: Lecanora rupicola and left: ?

And wait -what are those evenly coloured deep russet copper coloured patches with black apothecia?

It is one of the two look-alikes Tremelecia atrata and Rhizocarpon oederi (now Haugania  oederi) . Back home after talking to ChatGBT and looking at lots of internet pictures I plump for T. atrata because the apothecia are concave, the areole surface sunken, and the prothallus very black showing between the areoles.  I had scraped off a few apothecia- one day I may see if they have simple spores just to check. (H oederi has three septate spores). 

Here is a distribution map of Tremelecia atrata  Settle is just left of centre near the bottom in this map, and the location of the rock is just under the second t of Settle.  This point will get added.  

I also think I found this species on another single rock c 4km north of here, near Stainforth

At the corner of the reservoir wood wall I found Caloplaca (now Athallia) holocarpa. I pulled the small pebble sized loose stone out of the wall - I could take it home. "No I won't" I thought - "The lichens I bring home all die. It is better to leave it here and come and look for it another day.

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On a rock at the foot of the erratic boulder there was some of our "Pertusaria corallina that goes yellow and then orange with K but not red." This specimen was significantly grey rather than white (which made me think it might be P. pseudocorallina. close inspection showed that the isidia did not have dark tips.  (Though they were slightly dark... And this close inspection led me to noticing several black dots amongst the isidia. I shall call them the parasitic lichenicolous fungus ... and say "that proves it is P corallina." 

 though I am not very confident.

The yellow changed to orange after 25 minutes.

As it is the waxcap season (end of October) I have been looking for waxcaps.  I found heath wax cap and slimy wax cap and possibly cedar waxcap and apricot clubs. mostly in this 3 m wide strip of heathy grass just below the boulders. 

This Didontodon looking moss is grwoing in an acd place - It must be Ceratodon purpurea.

Xanthoparmelia conspersa - a big thallus but the only one I saw there.

Gliophorus laetus - Heath Waxcap 

See the flat field behind our big boulder in the wall

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