An amateur’s geological overview of the area where we live
There is no doubt that the Kerry, Sarn and Dolfor areas used to look very different from today’s beautiful and diverse scenery. Over the millennia our area has been sculpted by the forces of nature, namely; ice, water, weather and to a small extent volcanic activity and natural earth movements. Latterly, our farmers are doing a great job, influencing the natural environment and making the current countryside a lovely place in which to work and live.
A drive along the Vale of Kerry with Newtown behind you and Churchstoke in front gives a great impression and a few clues to the past. The undulating nature of the ground, the deeply incised valleys of the vale bluffs and the change of direction of river courses are all indicators that our area has been mildly glaciated. A quick glance at the farmed soils shows them to contain lots of stones and pebbles, they vary in fertility and where the rivers have eroded bare banks, they also vary massively in depth and colours. This complex picture is indicative of earth moved by ice, sometimes called drift and is evidenced in the area between the villages of Kerry and Sarn where there is a fantastic drumlin field. Sometimes this scenery is called ‘basket of eggs’ topography because it resembles just that from above. But from ground level and particularly from the A489 you get the impression of driving through gently rounded, bumpy fields. This is ground disturbed and probably pushed along in front of a slow-moving sheet of ice, which after melting deposited this distinctive evidence. The course of the river Mule was probably changed as well during this slow process, but evidence of this today is difficult to spot.
The higher ground either side of the Vale of Kerry and over towards Dolfor probably escaped the direct impact of the ice sheet. But likely it would have been exceptionally cold and barren of life for thousands of years. When the permafrost of the high ground melted the streams would have been enlarged and they eroded their courses even deeper, giving evidence of the depth of soils and its pebbly contents. Sometimes these streams and water-courses are called ‘misfits’ because the smaller volume of water they carry today would not have the erosive power to make the deep valleys in which they lie.
If you investigate the rocks that lie below the soil the geological picture becomes very complex and well beyond my scope in this article. Some of our older buildings are made of a local common stone, known as mudstone. It is a relatively soft sedimentary rock with a lovely grey-green colour and has the big advantage of being easily split along straight planes into flags used for walls or roofs. Other types of rock exist in our area of course and these have been mined or quarried and used as building materials for centuries. Most of our old quarries are now disused and some have found second agricultural uses, but a glimpse inside them often reveals what’s going on underground, if you are interested.
Article kindly submitted by Kerry resident, David Thornton