A Dry Valley

Once again I am going to sing the praises of my old geography teacher, Mr Cole. He taught at Ifield Grammar School in the 1960s. That was before that particular school decided they’d be better off without me – a decision, which in retrospect, was a superb one. My life flourished. Its life, I’m sorry to say, probably went downhill although as I was no longer a member, I couldn’t say.

But I will say that had they had more inspirational teachers then I might have been encouraged to work hard. Of course, Mr Cole wasn’t the only one, but he was the one that did most for me and my brother who had a more torrid time at the school than I did. I would love Mr Cole to read this and know that he made a difference. I’m guessing that he’d be in his mid-70s by now for he was a young teacher back then, tall and quite lanky and, I would say, a bit unsure of himself. He was given the duff classes – like mine and my brothers! I do hope he made a success of his career.

It was from Mr Cole that I learned about so much geography and today we look at a dry river valley quite near my home on Salisbury Plain.

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Now we know, because Mr Cole taught us, it is a river valley because it has a V shaped cross section. Had it been formed by a glacier it would have had a U shape. We also know it is a youthful river valley because it is going downhill in zig-zags with interlocking spurs.

But chalk is permeable and this is chalk land. Water just seeps into chalk and you don’t get rivers flowing on this rock.

But you did once and thanks again to good old Mr Cole for explaining. During the ice age water in the chalk froze and so the rock did become impenetrable to water. If rain fell – and it did – it had to flow off the hill as a river. It was frozen for long enough for the abrasive quality of the flowing water to wear away this valley.

When the temperature rose and the ice in the chalk thawed out, the rainwater, once again just seeped into the chalk to emerge at the spring line where the chalk met clay.

The photo sums up Salisbury Plain. It is very limited in distinguishing features. Once upon a time travellers got lost, particularly in bad weather, and died trying to find their way. Villagers near the Plain planted distinctive clumps of trees on the hill nearest the village and this results in some descriptive names. Near us there’s a clump called Chirton Maggot and another called Marden Cowbag.

This picture dates from 2002 but it still looks the same, of course.

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