The monument comprises a complex long cairn formed of three linked chambered cairns, visible as a series of stone structures set into a natural saddle-shaped ridge (210 m OD) on Essich Moor. The cairns are Neolithic, dating to the fourth millennium BC, and form part of the Orkney-Cromarty Group of chambered cairns identified by Henshall. The monument was first scheduled in 1964. The present rescheduling alters the scheduled area to reflect changes in the Ordnance Survey mapping.
The S cairn is heel-shaped and measures about 42.5 m from N-S by 36m transversely, and is 2.6 m high. The back slab is exposed and is 1.56 m long, 0.9 m high and 0.45 m thick. This is abutted to the SE by a slab 0.86 m long and 1 m high, and to the S by a slab 1 m long and 0.13 m thick. This chamber was cleared out in around 1918, producing some bone. The middle cairn is up to 1.6 m high and around 12 m in diameter. It includes a chamber flanked by a pair of portal stones 0.54 m apart. Only the back slab and side slab are visible. Two kerb stones lie 7.7 m W of the chamber. This middle cairn is clearly earlier than the cairn material that joins the S and N cairns. The N cairn lies 37 m from the S cairn and is oval in plan, measuring 44 m from NNE-SSW by 36 m transversely and 2.3 m in height. The entrance to the chamber is flanked by a stone measuring 0.6 m by 0.3 m and projecting 0.85 m. The chamber has been disturbed. The side slabs measure 1.75 and 1.86 m long by up to 0.33 and 0.35 m thick; both project 0.9 m. A putative displaced capstone is also evident.
The area proposed for scheduling is a clipped rectangle on plan, to include the remains described and an area around them within which related material may be expected to be found, as shown in red on the accompanying map. The adjacent pond is specifically excluded from the scheduling.
Statement of National Importance
The monument's archaeological significance can be expressed as follows:
Intrinsic characteristics: The monument is well preserved and is the largest of the long cairns in the Orkney-Cromarty chambered cairns group, with upstanding remains dating from the fourth millennium BC. Despite some disturbance by antiquarians in 1918, the monument retains evidence of three chambers and their associated cairn material. Given the site's current use as sparsely grazed pasture, it is likely that archaeologically significant deposits relating to the construction, use and abandonment of the structures remain in situ. In addition, it is likely that deposits survive that could provide data relating to the prehistoric environment.
The monument has considerable potential to enhance understanding of Neolithic ritual and funerary practice. Carn Glas represents the accumulated remains of repeated funerary activity on the same site, with at least four phases of construction evident, and therefore has the potential to provide information relating to a long period.
Contextual characteristics: The monument is a good representative of a numerous class, many examples of which have been destroyed or badly damaged by forestry operations in the modern period. Carn Glas is one of only 59 Orkney-Cromarty chambered cairns still extant. Its location within a wider pattern of early prehistoric ritual funerary activity in the surrounding area enhances its significance. The stone circle at Torbreck, for instance, lies 1 km to the NW and other chambered cairns, such as Culduthel, are just a few km away. In addition, it is surrounded by numerous hut circles, clearance cairns and cultivation remains, potentially relating to the Bronze or Iron Ages. Together, these elements enable an understanding of how prehistoric settlement and society developed over time.
Carn Glas is unusual in that it provides good views in all directions, despite not being on the highest point on Essich Moor.
In the near-absence of evidence for Neolithic settlement sites in the area, chambered cairns are one of the prime archaeological sources for an understanding of Neolithic society. The existence of several phases of construction provides a unique opportunity to obtain a better understanding of the development of funerary architecture on a single site over a period that could span decades, if not centuries.
Associative characteristics: The monument is the product of Neolithic funerary activities and it has survived due to the use of the moorland for the low-level grazing of sheep. It remains a prominent feature within the landscape and owing to its character is visually imposing. All editions of the Ordnance Survey record it as Carn Glas (which translates as grey cairn), suggesting a local awareness of the monument. The Neolithic monuments of Scotland retain a place in the national consciousness, with people visiting such sites regularly, often on dates of astronomical and hence ritual/religious significance, such as the summer solstice.
The monument is of national importance because it has an inherent potential to make a significant addition to the understanding of the past, in particular Neolithic society, the design and construction of chambered cairns, and the nature of Neolithic ritual and funerary practice. Its relatively good preservation and the survival of marked field characteristics enhance this potential. The loss of the example would significantly impede our ability to understand the Neolithic period in northern Scotland. The monument also has a place in the national consciousness, given the strong continued interest in the UK in the ritual monuments of early prehistory.