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High Pasture Cave Fieldwork Update - July 2007

Posted by steven on 24/07/2007 at 06:47 PM

Read on for a summary of fieldwork including the latest finds at the High Pastures site.....

As is usual with the weather in this part of Scotland - if it is wet south of the Border, Skye is generally dry and sunny! The weather here has been quite exceptional for the past few weeks with little rain, although the winds have been mainly from the North and Northeast. This has allowed us to proceed with fieldwork at the High Pastures site with few interuptions.

Trench 14

The excavations within Trench 14, which was initially laid out to investigate the two shieling structures at the site, has now reached the Iron Age and potentially earlier layers of archaeology. The image above shows a slot trench down the side of shieling number 2. Layers of fire-cracked stone can be seen in the baulk of the trench, the dark sediment layer of which has produced quite a few sherds of pottery and one vitrified crucible fragment. However, within the base of the trench we have identified several small features cut into the natural karstic clay.

These appear to be a pit-like feature filled with fire-cracked stone, which also contained a quantitiy of heavily burnt bone, and a slot-like feature packed with fragments of stone. The feature show in the image above also has a small stake-hole at one end, while a small fragment of Rum Bloodstone - a type of volcanic glass from the island of Rum in the Inner Hebrides used to make stone tools - was also recovered. In a third stone-filled feature we recovered part of a flint tool with microlithic retouch, which may suggest an early date for this feature. Therefore, we have decided to remove part of shieling number 2 and excavate down through the burnt mound deposits to investigate the make-up of this feature in this part of the site and to see if other features are visible cut into the natural clay below.

The image above shows the stone-filled feature containing the burnt bone fragments before excavation. The image below shows shieling number 2 and the location of the section line (2m scale) before the start of excavation. First of all we removed the stone walls of the shieling, which revealed courses of stonework that were masked by tumbled material beforehand.

The image below shows the excavation of the standing wall of the shieling to reveal the hidden foundation stones

The image below shows Kath Small from Ballachulish and Nicola McGaughey from Dunblane revealing the upper deposits of burnt mound/spreads after removal of shieling number 2. The burnt mound here, as elsewhere on site, comprises compact layers of fire-cracked stones and pebbles, charcoal flecks and small fragments of burnt bone. The excavations in this trench will now concentrate on removing the different layers comprising the burnt mounds/spreads, before we have the opportunity to investigate potential features cut into the natural clay below.

Trench 16

Work is also progressing in Trench 16, a one metre wide slot trench to investigate the burnt mound/spreads in the east sector of the site. After removal of the turf we recovered two half fragments of rotary quern stone in this trench, along with a small amount of rough paving or wall tumble at the west end of the trench. The image below shows the trench after initial cleaning with the paving or wall tumble at the far end (west), while the remainder of the trench comprises a compact layer of fire-cracked stones and pebbles.

After recording, we then removed the paving/wall tumble to reveal the burnt mound/spreads covering all of the trench. One small sherd of pottery was recovered from this layer, along with two pebbles that may have been used as tools. The image below shows Marlene Sayers of Ballachulish excavating in Trench 16 (groovy hat Marlene!).

Excavation in this trench will now start and investigate the nature and content of the burnt mound/spreads in this part of the site. This worl will include wet-sieving of sediments and the collection of bulk sediment samples for post-excavation analysis.

Trench 15

One of the major trenches under excavation at the site this year is Trench 15, within the forecourt area of the site to the south of the cave/stairwell entrance into Bone Passage. Excavations in Trench 2 in 2005 indicated the potential complexities in this part of the site with multiple hearth settings and their associated deposits, and a potential paved walkway accessing Bone Passage that pre-dates the construction of the stairwell. Initial excavations revealed a field wall possibly associated with the sheilings on site, stone revettment walls and more of the spreads of fire-cracked stone and pebbles. The latter includes some fragments of pottery, animal bone and large lumps of charcoal; while two small fragments of vitrified stone crucible and a possible smelting hearth base containing copper-alloy deposits.

Removal of the fire-cracked spreads has revealed several features to date including a section through a circular stone-built structure (see image above). The wall of the structure, which measures around 4.5 metres in diameter, only comprises between one and two courses of stone; while the excavation of the interior only produced charcoal and ash deposits, and two granite slabs that have been affected by high temperatures in or adjacent to a fire. It is possible that these may have formed the bases of small hearth settings.

At the end of its use, the structure had been back-filled with medium-sized granite and limestone boulders, along with fire-cracked stone and pebbles. The image below shows the southern half of the structure after section excavation, with the charcoal and ash layers visible at the base. Note the large granite boulder adjacent to the section line, which had been manourvered into position here.

The image above shows Lynn Fraser and Martin Wildgoose excavating in very different deposits in Trench 15, with the entrance to the stairwell beyond. Lynn is removing compact layers of fire-cracked stone, while Martin is working his way through a dark black, organic-rich sediment at the north end of the trench. Martin recovered quite a few fragments of pottery in this part of the trench including several rim sherds. This sediment extended up to and abutted a stone revetment wall. The image below shows Trench 15 from the northwest, with the dark organic-rich sediment evident at the front edge of the trench, with the low revettment wall beyond.

The excavations within Trench 15 have also just revealed a second cell-like structure around 1.8 metres in diameter (see image below). The cell appears as an arc of upright stones set into the layers of fire-cracked stone, with two prominent pillar stones. Again, the fire-cracked stone appears to have run in over the top of the structure, while several voids between larger stones hints at a back-filled feature.

The image above shows this ephemeral structure from above, along with some of the fills within the interior. Preliminary excavations within the structure over the past week have revealed an initial loose boulder fill and associated sediment, with large voids between some of the stones. After running a section through the structure and removal of the upper layers of loose fill, we have revealed additional courses of stonework (walling) and what appears to be collapsed stonework in the base. This may be collapsed corbelling - a former roof structure over the cell, although this requires further work. Although the loose fill and voids are still appearing within the structure, layers of sediments rich in ash and large lumps of roundwood charcoal are also present. We have also recovered some un-burnt animal bone and Red Deer antler fragments from the interior fills, along with a small periwinkle midden, a sherd of pottery and a small fragment of copper-alloy strap. Work will continue on this complex area of the site throughout the duration of this years fieldwork.

We have also started to remove the sediment and boulder fill from between the two revettment walls in the south end of the trench. These features arc around and respect the excavated ‘cavers’ entrance into High Pasture Cave and may have been some early form of floodwater control, diverting excess water from the flooded sink entrance down this fissure. If so, then it is possible that this entrance was also open at the same time as the stairwell and entrance to Bone Passage was in use. The view below shows Graham Parry from Dunan, Skye, removing the core sediments from between the two wall. The ‘cavers’ entrance is just out of shot to the right.

Trench 17 - Bone Passage

Elsewhere on site, excavations have continued in Bone Passage with the excavations in Trench 17. It is now evident that the deposits at the north end of Bone Passage are quite different to those at the south end, adjacent to the stairwell/cave entrance. Although we are recovering small fragments of degraded bone, burnt bone, shellfish remains and fragments of fire-cracked stone; we have not recovered any small finds. This is in stark contrast to the numbers of finds that we made at the other end of the passage, especially where the stairwell meets the natural limestone cave. The sediments in this part of the passage contain significant amounts of washed gravels, which may indicate that the archaeological deposits here have been subjected to water erosion and mixing, and it is possible that the deposits may be much earlier in date.

However, despite the lack of finds within the sediments here, we are still 100% wet-sieving the archaeological deposits - the image above shows Sally Parry from Dunan, Skye, busy at the wet-sieving area.

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