Erratic Boulder

 Erratic Boulder

In Dorset Barrow I explained that Bournemouth, Christchurch, and Poole were all on or near a plateau of gravel.

This plateau that must be dated to some time in the last million years has been cut through in many places, and as a result the area is dotted with steep roads. These hilly roads are notorious. Richmond Hill in central Bournemouth, Sea Road in Boscombe, Gravel Hill in Poole. As a cyclist in the area, these hills were a bugger to cycle up, and a quick thrill to ride down.

Separating the Bournemouth plateau from St Catherine's Hill,  north of Christchurch,  is a wide valley joining Ringwood in the North with the south coast at Bournemouth Bay, close to Hengistbury Head. 

The River Avon wandered through this wide valley, and in the 1960s the powers-that-be decided to build a dual carriageway along it, linking Bournemouth to Ringwood. 

The whole route was farmland,  and when the machines started to strip the soil to lay the footings of the new road, I and other members of the Archaeology group I belonged to were there, watching the ground they were cutting into, hoping to find stuff, anything,  but no, it was not to be.

I had rather thought that the valley had been cut through by the River Avon meandering across it, but I was wrong. Had that been the case the earth would have been disturbed,  perhaps brown or muddy, or so I thought. 

In fact the whole floor of the valley,  flat as it was, consisted of bright yellow sand.

Watching the huge earth moving mechanical beasts rolling along valley floor rather dashed our hopes of finding anything at all.

There was just the one thing though. That one thing was a huge limestone boulder just buried in the yellow stuff. When the Archaeology group found this there was a lot of tooth sucking and it was generally agreed that this must have been a glacial erratic. 

It was a big lump of rock, and must have been a metre diameter,  white stone, knobbly, probably limestone. 

I didn't think much about the ins and outs of the valley of yellow sand and the erratic in it at the time. I just stored it up to revive at a later date, if needed.

As far I understand it the nearest likely source for the erratic would be at or near the Cotswold hills which is considerable distance for a rock to be rolled. Fifty, a hundred miles? While the Bournemouth plateau was made up of gravel, this yellow stuff was not therefore local, so both sand and boulder both had to have come come from elsewhere.  I couldn't see the boulder and sand arriving in a glacier. It had to come by melt water,  and there had to be a lot of it!

As for the boulder, that was lifted by a charismatic member of the Archaeology group. He hired a crane and a flatbed truck, and removed it to become a feature in his own garden.

I have no doubt that it's still there!

Jeffery Nicholls 




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