Geological Mystery

As soon as he was back from the Antarctic, Trevor Potts, who runs the Ardnamurchan Campsite, began work on clearing a site for his new house. The groundwork is being done by Hughie MacLachlan of local firm H MacLachlan Contracts.

This shows the slope to the left of the first picture, where Hughie has dug back into layers of Jurassic shale and limestone, but one area, shown to the right of this photo, seems to cut vertically through the sedimentary layers. At first sight it might be an igneous dyke, but it yielded some very strange structures.

These balls, a bit bigger than a golf ball, are embedded in the rock - the one on the left is still stuck in to a chunk of it. When broken open, they don't seem to have any structure.

It's difficult to tell whether they are of igneous origin or not. In many ways, they resemble the concretions that can be found in shales, such as the famous ones at Whitby and Robin Hood's Bay in Yorkshire - but these won't be found in a dyke.

To add to the mystery, an elongated tube-like structure of uniform cross-section runs up at an angle through the dyke. It, too, has these 'balls' embedded in it.

If anyone has any idea what these may be, we would be very interested to hear. Trevor has preserved the exposure, which will be at the back of his house, as well as a number of the 'balls' and sections of the 'tube'.

Trevor runs the Ardnamurchan Campsite, website here.