i am a drainlayer in New Zealand,,<br>i dig in Auckland,,lots of volcanic stuff,,in Sth Island,,(another tectonic plate) it's all gravel,or sand..<br>i dig through concretions sometimes,,,<br>i jump out the digger and tittoo with a trowel,,pulling out the little layers,,such fun,,um ( Moeraki  Boulders are a good example)