At that time the rocks that now comprise most of Scotland (and part of the northern Irish landmass) were not attached to Avalonia.

The line of joining, or suture, is approximately under the Solway Firth and Cheviot Hills.

In the Lake District, the junction between the early Ordovician series, Skiddaw Slate, and the Borrowdale Volcanic that was forced under it, can be seen on the slopes of Fleetwith Pike.

In the English Lake District, the Borrowdale Volcanic Group is composed of lavas (mainly andesites), tuffs and agglomerates, along with some major igneous intrusions.

[1] The outcrop of this sequence on Crinkle Crags (and other surrounding peaks in the Lake District), was chosen as one of the top 100 geosites in the United Kingdom by the Geological Society of London.