The Cleveland Dyke is a band of igneous rock that was injected, whilst molten, into the local rocks during the Tertiary period of geological time (approx 60 million years ago). The dyke originated in a large magma chamber beneath the Island of Mull on the west coast of Scotland and has been estimated to have taken between 1-5 days to travel to North Yorkshire.
Looking from Cliff Rigg Quarry to the Langbaurgh Ridge. The old quarry sites along the ridge can be seen between the trees. I have often wondered whether the people who lived in this area during prehistory used the Langbaurgh Ridge as a routeway from the River Tees to the moorlands. Bronze Age burials have been found in Ingleby Barwick close to the outcrop of the dyke. There are many prehistoric sites around the outcroppings on the North York Moors, particularly on Fylingdales Moor.
The dyke is mainly buried beneath glacial deposits but outcrops at a number of locations across Cleveland and the North York Moors. Where ever the dyke outcrops it has generally been quarried away. The rock, a basaltic andesite but popularly known as whinstone, it is a very hard rock and was ideal for road building both as a hardcore and to make setts and blocks for surfacing.
During the late 1800’s Leeds Corporation operated the quarries at Cliff Rigg just outside Great Ayton. The Middlesbrough to Whitby railway runs just beneath the quarry so it was possible to extract the stone and ship it by rail to Leeds.
Ironstone was also mined at Cliff Rigg and the surrounding area.
The Smell of Water 
The dyke outcrops in my mind were definitely respected and used by the Prehistoric peoples of the Cleveland area ive studied the dyke on foot from Thornaby to cliff rig , I believe the outcrop at Stainsby beck was a sacrificial site , also what would have been a large outcrop at stainton was used as a monument , meeting place incorporating Boltonmos hill , the Basalt in this outcrop also has a very unusual magnetic attraction .
Cheers Heath, I visit your blog regularly and am fascinated by your discoveries.
Sorry I never replied I never got any notifications, thanks for the comment regarding my blog.
I tested approx. 8 miles of the dyke some years ago now testing both outcrops and surface deposits for there magnetism, starting with the stainsby beck outcrop and ending at Cliff rig quarry, samples from the Stainton outcrop attracted a magnet far better than any other samples, in fact some samples tested from the Stainton outcrop including a left over cobble actually reversed a compass reading as I approached it from approximately 3 metres away.
Hi Heath, so what does the magnetism indicate? that there is magnetite or haematite within the dyke rock or is the magnetism coming from the country rocks?
Sorry mate only 2 years late, yes the dyke in sections has a very high magnetite content, but also titanomagnetite.
Remember the rock cooled rapidly at a time of reversed polarisation, it still holds that signature.
Not sure I understand the significance of what you are saying. Aren’t polar reversals fairly normal events that happen relatively frequently over geological time?
In my days working on seismic surveys we used to do gravity & magnetometer surveys where we would measure the magnetic alignments of the strata to help with dating