The 1960s excavations at Mid Gleniron provided an early indication of the multi-period nature of chambered tombs.
Mid Gleniron I started as rectangular chamber in a round cairn. This was followed by a second similar burial. These two cairns were then incorporated in a long cairn with a crescentic facade and a third burial added between the first two.
Mid Gleniron II also also started as rectangular chamber in a round cairn which was then later incorporated in a rectangular cairn with a second chamber.