Cairnfields are groups of cairns. They may have only a few cairns or many tens, such as Chatton Sandyford, Northumberland. They are believed to have been built with stones from the surrounding area to make it easier for farming, called clearance cairns, but may also be funerary with inhumations or cremations beneath. Even in the event of excavation it may still difficult to decide on a purpose. They are usually found in upland areas, but they may once have been more widely spread. They are mainly believed to belong to the Bronze Age when much upland was first opened up for farming - but they could well have be re-use of the material or the individual cairns for religious rituals. A Iron Age pin was recovered from an Alnham cairn.