Rock fences are interesting to take a look at. They usually reflect local geology remarkably well because it is expensive to transport such a heavy material which is readily available in most places. Here I present a collection of images of rock fences and walls I have taken so far.
Unfortunately my collection is very small but this post in its current state is just a start. I plan to update it as I take new photos. Now I have a reason to hunt these walls and a place where to upload the photos.
Ignimbrite (welded tuff). Gran Canaria, Canary Islands, Spain.
Mudstone (turbidite). Cliffs of Moher, Ireland.
Andesite or basaltic andesite. Red blocks are weathered. Santorini, Greece.
Quartzite. Connemara, Ireland.
Basalt or basanite. La Palma, Canary Islands, Spain.
tuff (ignimbrite). Gran Canaria, Canary Islands, Spain.
Quartzite. Santorini, Greece.
Ignimbrite. Tenerife, Canary Islands, Spain.
These rocks may look like man-made bricks but they have entirely natural composition. This is the same Tenerife ignimbrite shown in the previous picture.
Pumiceous lapillistone (pumice fall deposit known as Granadilla pumice), Tenerife, Canary Islands, Spain.
Wall made of gneiss in Sweden.
It was noted in the Roadside Geology of Indiana, that if you look at foundations of buildings built before railroads and away from navigable waterways, that the foundation stone is typically local stone as well. In Europe this might also apply to older buildings.
Yes, it seems to be the case. In my home country northern part of it has limestone bedrock and southern has weakly cemented sandstone which can not be used as a building material. Limestone houses are common in the north but almost absent in the south. Although Estonia is a small country, ony few hundred kilometers from one end to another. There are old stone houses in the south but they are made of granite and gneiss (glacial drift rocks).
really great idea