Green Bank: Where the Ice Met its Match

Yesterday’s post about Hagg’s Gate set me off thinking, descending yet another rabbit hole: about the time the last glacier flowed down the Vale of York and slammed into the Cleveland Hills. About the time that ice sheet politely stopped at the hills’ feet. About the time these great north and west escarpments of the North York Moors were begrudgingly taking shape.

Elgee argued that during this last Ice Age the hills themselves put up some resistance but eventually receded, lopping off the heads of the Bilsdale valley and its tributaries. In other words, the cols at Hagg’s Gate, Garfit Gap, Donna Cross, and Green Bank are all that remain to hint at the valleys that once reached much further north, before erosion turned them into the escarpment we now so familiar with. These cols, incidentally, bear no great resemblance to one another. Hagg’s Gate is a narrow notch, much like the dry upper reaches of Bilsdale, which, despite appearances, must have been once gouged much deeper by water. Green Bank and upper Raisdale, however, could easily pass for an airstrip, being so broad and flat¹Elgee, Frank (1912). The Moorlands of North-Eastern Yorkshire: their natural history and origin. Page 236. London: A Brown & Sons. OCLC 776748510..

While descending Carlton Bank on my ever-faithful bike, I paused to admire the sheer drop of Green Bank. One can almost picture the towering ice wall, careering southwards, reluctantly deflected by these hills, clawing and scraping away at the obliging shales.

Today, that once dramatic slope is meekly trying to reach some sensible angle, worn down by solifluction—the tedious downhill creep of debris—and the occasional landslip to keep things interesting. The photo, of course, fails miserably to capture the actual steepness of the slope.

There is a charming feature of Alpine glaciers called a “randkluft”: a nice little gap between the glacier and the rock, formed by the tiresome habit of ice melting against warmer stone. It yawns wider in summer and shrinks again in winter. One wonders whether some such a randkluft could have graced Green Bank once, back when the ice had grander ambitions.

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  Elgee, Frank (1912). The Moorlands of North-Eastern Yorkshire: their natural history and origin. Page 236. London: A Brown & Sons. OCLC 776748510.