The Evolution of Britains Landscape.
Scotland come together: Ordovician(510-439 Ma.)
and Silurian (439-408 Ma.) ( Lower Palaeozoic) times. Part 1 of 3
Ordovician times, most of Scotland and N. Ireland were separated
from England & Wales by a wide ocean called Iapetus.
The Skiddaw Slates (or Skiddaw Group) of the Lake District consist of metamorphosed marine sediments laid down on the northern margin of Avalonia. These slates can now be seen in the northern part of the Lake District, e.g. around Blencathra and Skiddaw. Have a look at some chiastolite slate.
for part 2