Page 24 - Cracking Walks - Energetic

Cracking Walks around Crickhowell
Geology
The Black Mountains mostly consist of Old Red Sandstone from the Devonian Period, sedimentary rocks laid down 400 million years ago when Britain and Europe were south of the Equator and connected to North America. The reddish colour comes from oxidized iron.
Carboniferous (i.e. coal bearing) limestone once covered the Black Mountains area but glacial action through successive ice ages wore this away and only a thin remnant survives at Pen Cerrig-calch. The softer layers of sandstone were worn down, creating river valleys and sculpting the rounded shapes of the Black Mountains.
To the south of the River Usk and Crickhowell limestone dominates the landscape. Two hundred years of quarrying has created the dramatic cliffs at the Llangattock escarpment (Walks 5 and 6).
Over millions of years the limestone has been eroded by mildly acidic rain water to form extensive cave systems and surface sink holes (dolines).
Birds
Spring sees the upper slopes of the high moorland alive with Wheatear and Meadow Pipit. Whinchat also arrive to join the resident Stonechat and Golden Plover move through on migration with a few staying to breed.
Red Kites and Ravens are increasingly common, and a pair of Peregrine Falcons breed regularly on Craig y Cilau (see below). Dippers are found all along the Usk and its tributary river valleys, along with Grey Wagtail, Pied Wagtail, Grey Heron, Goosander and if you’re lucky, the wonderful electric blue flash of a Kingfisher.
Welsh Mountain Ponies
The tough little ponies you see roaming the hills are semi-wild; they are all owned, rounded up and checked every year.
They all need passports and have to be registered and chipped. Their hardiness in battle impressed Julius Caesar, who took some of them back to Rome. Less impressed was Henry VIII, who ordered their slaughter, as he was keen to improve the stock of war horses and wanted smaller breeds eliminated. Fortunately their isolation on the inhospitable hills helped them to survive.
Craig y Cilau
This National Nature Reserve, visited in Walk 6, is one of the largest upland limestone cliffs in Wales.
It is home to rare whitebeam trees and many other limestone loving plants, and the cave system underneath the escarpment is an important habitat for the lesser horseshoe bat.
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