Gask House Tower

Report of 1965 and 1966 excavations by Prof A.S.Robertson and Mr J.Thomson

The full text of this report can be found in A.S.Robertson “Roman ‘Signal Stations’ on the Gask Ridge”, Transactions of the Perthshire Society of Natural Science (Archaeological and Historical Section), Special Issue, 1974.

In 1965, the Archaeological Section of the Perthshire Society of Natural Science initiated a project to excavate or re-excavate at least one of the Gask Ridge “signal stations” in the hope of finding dateable evidence. Gask House (NN990191) was the site chosen, since although it had been investigated briefly by Dr Christison, further trenching near the ditch-end might, it was thought, bring to light some pottery or other dating material. Accordingly, in 1965, a trial trench was opened up, and further excavated in 1966. The work was supervised by Mr James Thomson, Curator of the Smith Art Gallery and Museum, Stirling, and myself.

Since the ditch of the “signal station” and the bank inside it were visible on the ground, a surface survey was made, and a trench (T1), 4′ (1.22m) wide, was then laid out from the ditch near its end on the east side of the north causeway, southwards across the site. The trench, 80′ (24.4m) long, was aligned slightly askew to the presumed axis of the signal post in the hope of locating at least one of the internal post-holes. A post-hole was in fact found in T’1, and two other smaller trenches (T’3 and 4) revealed two other post-holes. All three were over 2′ (.61m) in diam, and went down 2′ (.61m) into the subsoil. Charred wood and some packing stones were present in each, and in two, in Trenches 1 and 4, there was a flat stone on the bottom. The presumed position of the fourth post-hole has been dotted in on the plan.

These four holes must have held the four great corner posts of a wooden tower, whose dimensions may be given as about 10′ (3.05m), from east to west, and 8′ (2.44m) from north to south. It depends of course on whether measurements are taken from centre to centre of the post-holes, or from their inner or outer edges.

The post-hole first found in the 80′ (24.4m) Trench 1 was partly under the east side of the trench, so that a small trench (T’1e) was cut eastwards to reveal the entire post-hole. The eastern tip of Trench 1e located the inner edge of the encircling bank, and established a point on its circuit.

Trench 1 also revealed the remains of the bank. It was 9′ (2.74m) wide, and had a layer of turf at the bottom, and clay upcast from the ditch above. The turf had been laid and presumably represented stripping of the surface before the ditch was dug. The bank, with its turf underlay, survived to a height of only 1′ (.3m).

At the north end of T’1, the bank was evidently coming to an end within the width of the trench, and had run out altogether on the SW side of the trench. The points established on the inner and outer edges of the bank, and the position of the four post-holes indicate that the area enclosed by the bank was not circular, but rectangular with rounded corners. It measured 22′ (6.7m) from east to west, and 18′ (5.49m) from north to south. Within this sub-rectangular area the wooden tower framed by the post-holes was set back from the centre, leaving a space of about 2′ (.61m) between the two southerly post-holes and the bank, and about 5′ (1.52m) between the two northerly post-holes and the bank. Such a position would provide more space for men entering and leaving the tower.

The encircling ditch on the other hand was shown by its visible trench to have been more nearly circular, if with its east and west sides somewhat flattened. It was roughly “V” shaped in profile. Its depth averaged about 3′ (.9m) from the top of the clay subsoil. Its greatest width was on the south side, 11′ (3.35m), while its width on the east and west sides was about 9′ (2.7m), measured on the surface. It narrowed to 6′ (1.8m) in the section at the north end of Trench 1. The ditch was clearly beginning to run out at the north end of Trench 1, and its precise ending was located in an east-west trench (T’2) cut across the visible causeway between the ditch-ends. The causeway (or more accurately the strip of ground left undisturbed when the ditch was dug) was less than 9′ (2.7m) wide. There were some stones trampled into the surface of the causeway and on the ditch-edges. There was natural silting in the ditch.

The axis of the “signal station” is shown by the position of the post-holes, and by the gaps in the mound and ditch, to have been slightly west of north.

The finds were scanty in the extreme: only a few flecks of charred wood, three iron nails (much corroded), and a mortarium rim. This latter was found unstratified in dark soil about 2′ (.61m) behind the bank in Trench 1 (at a point marked X picture link). Fortunately the mortarium was of a distinctive type. Mrs. Katharine Hartley most kindly supplied the following note on it:

“The Gask mortarium is particularly useful as both date and origin are beyond doubt. It is in every way a typical Flavian product of the extensive potteries near Watling Street, in the area south of Verulamium, and including Brockley Hill and Radlett. The rim-form can be most clearly matched in the work of Albinus and it could well be one of his products, especially as he made more mortaria than any contemporary potter. His activity can be dated c.A.D. 70-95, and there can be no doubt that the Gask mortarium was made within this period.”

A long term research project to study the Romans north of the Antonine Wall