Hallaig Fossil Hunting

1920 – The shore and waterfall succession documented
G.W. Lee’s Geological Survey memoir, with palaeontological work by S.S. Buckman, recorded measured beds and fossil assemblages around Hallaig Bay, the waterfall and the shore to the north. Its separate limestone, sandy and shale sections remain valuable records of the exposures, although some fossil names and stratigraphic terminology have since changed.

1956 – A numbered framework for the main fossil shore
M.K. Howarth described the Scalpay Sandstone succession and the transition from the underlying Pabay Shale at Hallaig. His numbered beds, including the first continuous sandstone used as the local formation base, became the framework for later correlation and the modern account of the main foreshore.

1985 – Ammonites refine the age of the lower sandstone
Phelps revised the early Pliensbachian ammonite succession. At Hallaig, Beaniceras in Howarth’s Bed 11 showed that it belongs to the Ibex Zone rather than the younger Davoei Zone. The revised fossil sequence improved the placement of boundaries through the Pabay–Scalpay transition.

1985 – The landslip reconstructed from repeated strata
Russell’s detailed mapping recognised the same Jurassic rock succession in the backface and within the displaced Hallaig landslip. Dip measurements, cross-sections and stability analysis supported rotational movement with a failure surface in the Pabay Shale, explaining why intact blocks and strongly deformed shale occur side by side.

1995 – Rare ammonites reported from the southern limestones
Ammonite material spotted by John Hanson in the Breakish Formation section on the west side of Hallaig Bay was published as Franziceras ruidum. The specimens came from a precisely recorded limestone horizon, providing unusual age evidence in a succession where ammonites are very scarce. The collection date itself was not established in the published account.

1998 – The Hallaig Sandstone Member formally defined
S.P. Hesselbo, M.J. Oates and H.C. Jenkyns formally defined the Hallaig Sandstone Member, using Hallaig Waterfall as its type locality in their account of the Hebrides Basin. Their interpretation helped clarify the repeated deepening and shallowing of the Early Jurassic sea. BGS subsequently retained the member within the Ardnish Formation rather than the enlarged Pabay Shale used in that paper.

1999 – An ammonite named for Sorley MacLean
Nicol Morton described the southern-bay specimens as the new species Franziceras sorleyi, honouring the Gaelic poet. The holotype and associated fragment were deposited in the Hunterian Museum, University of Glasgow. Their position 0.80 m above the base of Bed 34 established a middle Hettangian Liasicus Zone horizon and showed that marine deposition began earlier here than had previously been assumed from regional comparisons.

2002 – A new lobster from the northern landslip
R.M. Feldmann, G. Crisp and D. Pirrie described Pseudoglyphea foersteri from a loose Scalpay Sandstone block found by Glen Crisp in the northern Hallaig landslip, beyond the core measured foreshore section. The holotype is held by the Natural History Museum, London. Associated ammonite evidence places the block in the Pliensbachian Davoei Zone; its original numbered bed is unknown.

2004 – The transition recognised in the Geological Conservation Review
The Hallaig Shore account in the national Geological Conservation Review brought together the measured beds, fossil records and landslip structure. It highlighted the shore’s importance as the best documented Pabay Shale–Scalpay Sandstone transition in the northern Hebrides Basin, while distinguishing the coherent main log from the disrupted exposures to the south.

2020 – Fossil shells contribute to isotope research
Fossil shells from Hallaig Waterfall were included in research by S.P. Hesselbo, C. Korte, C.V. Ullmann and A.L. Ebbesen on Early Jurassic carbon and oxygen isotopes. The study examined records of seawater and later alteration across several British sections, extending the scientific use of Hallaig’s fossils beyond identification and bed-by-bed dating.

This account separates three published sections: the older limestones on the west side of the southern bay towards Rubha na Leac; the waterfall-area sandy succession; and the Pabay–Scalpay section north of Hallaig township. Beds are described upwards within each section. Morton’s 1999 numbers, Lee’s 1920 numbers and Howarth’s 1956 numbers are independent schemes: the same number does not identify the same rock in different sections. Landslips, gaps and inaccessible cliffs prevent these observations from forming one continuously walkable or completely measured succession.

Stornoway Formation: older context at Rubha na Leac

The promontory at Rubha na Leac exposes Triassic terrestrial breccias and conglomerates, sandstone, siltstone and calcrete. They record alluvial fans, streams and floodplain soils before the Lower Jurassic marine succession. This is the separate southern approach context, not the fossil-bearing Pabay–Scalpay shore north of Hallaig. The contact beneath the Breakish section is concealed by raised-beach deposits and landslipped material; approximately 10 m of unexposed strata was estimated beneath the lowest logged Breakish beds.

LIAS GROUP

The Breakish, Ardnish, Pabay Shale and Scalpay Sandstone formations are Lower Jurassic units of the Lias Group. “Lower Broadford Beds”, “Upper Broadford Beds”, “Pabba Shales” and “Scalpa Sandstone” occur in older literature. They are historical terminology, not additional formations to place alongside the modern units.

Breakish Formation

The separate southern-bay section comprises about 35 m of predominantly marine limestone and shale. Morton’s Beds 1–17 lie on the shore around NG 5961 3811; Beds 18–47 are principally in the low cliff west of the bay, around NG 5956 3809. A branching dolerite sill intrudes the lower shore beds and cuts progressively higher levels southwards. Contacts may be altered by heating. The following thicknesses are those in the measured column, including its identified gaps, and are not a complete thickness of the formation.

The beds below use Morton’s 1999 numbering. Shell-rich micritic limestones and dark shales dominate; nodularity, burrows and shell banks record a biologically active shallow-marine environment. The ammonite horizon in Bed 34 is securely middle Hettangian, but a precise ammonite-zone assignment is not demonstrated for every limestone above and below it.

Morton Bed 1 (0.75 m)
A blue-grey, fine-grained limestone, slightly nodular, with irregular dark shale seams and fragments of bivalves and gastropods.

Morton Bed 2 (1.83 m)
An unexposed interval. Its thickness belongs to the measured section, but its lithology cannot be supplied from the exposure.

Morton Bed 3 (0.60 m)
Blue-grey limestone with uneven dark shale partings; Modiolus is recorded.

Morton Bed 4 (1.50 m)
A further gap in exposure; no bed lithology is established here.

Morton Bed 5 (0.65 m)
Grey, somewhat sandy limestone interleaved with shale. Fossils include Liostrea and pectinid bivalves.

Morton Bed 6 (0.60 m)
Grey sandy limestone with shale partings and broken Liostrea shells.

Morton Bed 7 (1.40 m)
A poorly exposed interval occupied in places by a leaf of the dolerite sill. It must not be treated as a measured thickness of one sedimentary rock type.

Morton Bed 8 (0.15 m)
A thin, dark-grey, mud-rich limestone containing Liostrea and other shell debris.

Morton Bed 9 (1.60 m)
Medium- to dark-grey limestones separated by dark shale partings, with Liostrea.

Morton Bed 10 (0.78 m)
Blue-grey limestones with a small sand component alternate with dark calcareous shale.

Morton Bed 11 (0.70 m)
Dark-grey shale separates the more resistant limestone packages above and below.

Morton Bed 12 (1.10 m)
Grey, fine-grained limestone which weathers as a comparatively massive unit.

Morton Bed 13 (0.10 m)
A thin dark-grey shale interbed.

Morton Bed 14 (1.60 m)
Grey, fine-grained limestone; weathering reveals a nodular structure locally.

Morton Bed 15 (0.10 m)
A second thin dark-grey shale interbed.

Morton Bed 16 (0.90 m)
Medium-grey limestone containing a little sand, with Liostrea towards its top.

Morton Bed 17 (1.20 m)
Dark-grey shale that becomes brown on weathering. Plagiostoma and Cardinia are recorded.

Morton Bed 18 (0.40 m)
Grey nodular limestone with a pale weathered surface, at the base of the principal cliff part of the log.

Morton Bed 19 (0.92 m)
Medium- to dark-grey micritic limestone, relatively massive, with shale seams that weather reddish. Sand-sized particles include echinoderm and bivalve debris.

Morton Bed 20 (0.70 m)
Dark-grey micritic limestone with scattered small skeletal fragments.

Morton Bed 21 (0.12 m)
Dark-grey to black laminated shale.

Morton Bed 22 (0.38 m)
A paler, medium- to light-grey micritic limestone with coarse-sand-sized echinoderm and bivalve debris.

Morton Bed 23 (0.15 m)
Black fissile shale, forming a recessed ledge.

Shared character of Beds 24–31. These closely spaced beds alternate light- to medium-grey shell-rich micritic limestone with medium-grey to black shale. Liostrea is abundant locally, forming oyster-rich concentrations. The package makes a recess at the foot of the cliff; the individual layers are retained below rather than combined into one bed.

Morton Bed 24 (0.14 m)
A thin limestone within the closely alternating limestone–shale package at the foot of the cliff.

Morton Bed 25 (0.20 m)
A shale layer within the same shell-rich alternating package.

Morton Bed 26 (0.32 m)
Shell-rich limestone within the alternating package.

Morton Bed 27 (0.15 m)
A shale interbed separating the shelly limestone below from the very thin limestone above.

Morton Bed 28 (0.02 m)
An exceptionally thin limestone layer within the shale-dominated part of the alternating package.

Morton Bed 29 (0.24 m)
A shale interbed.

Morton Bed 30 (0.15 m)
Another thin limestone layer in the alternating package.

Morton Bed 31 (0.21 m)
The upper shale layer of this closely spaced limestone–shale package.

Morton Bed 32 (0.32 m)
Pale nodular limestone above the thin alternations.

Morton Bed 33 (0.27 m)
Medium-grey shell-rich limestone containing numerous Liostrea. The published column carries a general ammonite annotation beside this bed; the explicitly documented Franziceras sorleyi specimens are assigned in the text and specimen captions to Bed 34.

Morton Bed 34 (1.20 m)
Light-grey micritic limestone in thin, nodular beds, with some bivalves. Large Thalassinoides burrows occur on lower bedding surfaces. The two specimens described as Franziceras sorleyi came from 0.80 m above the base; they identify the Liasicus Zone of the middle Hettangian.

Morton Bed 35 (2.10 m)
Medium- to light-grey nodular micritic limestone in thin beds, weathering nearly white. Scattered fossils include Liostrea, pectinids and gastropods; large Thalassinoides burrows also occur. This resistant package forms a prominent overhang.

Morton Bed 36 (1.00 m)
Medium-grey limestone in thicker beds with thin shale separations.

Morton Bed 37 (1.12 m)
Medium- to light-grey oolitic limestone with bivalve fragments. It is bedded, weathers white and presents relatively smooth surfaces.

Morton Bed 38 (1.40 m)
Medium- to light-grey fine-grained limestone with shell-rich and oolitic bands, also weathering relatively smoothly. Beds 37 and 38 form the only oolitic interval identified in this measured section.

Morton Bed 39 (0.45 m)
Dark-grey shale with thin bivalve shells, particularly pectinids.

Morton Bed 40 (0.20 m)
A thin, medium-grey nodular limestone.

Morton Bed 41 (3.80 m)
A thick package of medium- to light-grey, thinly bedded nodular limestone with shelly layers containing Liostrea, pectinids and Modiolus. Rubbly weathering and an upper overhang distinguish it in the cliff.

Morton Bed 42 (0.60 m)
Medium- to dark-grey shale with fragments of Liostrea and pectinid shells.

Morton Bed 43 (1.10 m)
Thinly bedded nodular limestone containing bivalve and gastropod fragments.

Morton Bed 44 (0.20 m)
A dark-grey shale interbed.

Morton Bed 45 (0.70 m)
Medium- to light-grey, mud-rich limestone containing bivalves.

Morton Bed 46 (0.30 m)
Dark-grey shale immediately beneath the highest numbered limestone.

Morton Bed 47 (1.00 m)
Grey limestone, nodular towards its base. The succeeding interval up to the younger sandy succession is not continuously exposed.

Unexposed interval above the Breakish log. The top of this measured section cannot be connected continuously to the younger sandy rocks near the waterfall. A gap of about 10 m appears in earlier diagrams, but Morton’s mapping-based comparison indicates that this substantially underestimates the missing succession. Its true thickness and lithological division are not securely measured here. It would be misleading to close the gap with beds borrowed from Skye or Applecross.

Ardnish Formation

Sinemurian sandy and shelly rocks form the waterfall cliffs and the ground immediately below them. The lower part includes limestone and fissile mudstone; higher parts become calcareous siltstone and mica-rich sandstone. Bivalves, brachiopods and crinoids are recorded, with Arnioceras and Euagassiceras providing ammonite evidence within this succession. It is not the same section as the Pliensbachian shale–sandstone transition farther north.

Lee’s 1920 Survey memoir records the following beds in the waterfall-area succession, in a numbering system extending beyond his older “Broadford Beds” log. The original feet and inches are retained, followed by rounded metric conversions. These historical beds preserve useful local observations, but their boundaries have not been matched bed-for-bed to Morton’s southern-bay log or to a modern member boundary.

Lee Bed 45: 4 ft (about 1.22 m)
Hard brown sandy limestone. A basal shell band marks the first appearance in Lee’s log of Gryphaea compared with G. arcuata. He described a small, narrow shell, less curved than typical G. arcuata and lacking its sulcus (groove).

Lee Bed 46: 6 in (about 0.15 m)
A thin sandy shale.

Lee Bed 47: 3 ft (about 0.91 m)
Brown sandy limestone.

Lee Bed 48: 6 in (about 0.15 m)
A second thin sandy shale.

Lee Bed 49: 10 ft (about 3.05 m)
Brown sandy limestone with a basal Gryphaea band. Lee observed the same small, narrow, weakly curved shells without a sulcus as in Bed 45.

Lee Bed 50: 10 ft (about 3.05 m)
Sandy shale rich in mica.

Lee Bed 51: 10 ft (about 3.05 m)
Hard sandy shale with a few Gryphaea shells. Lee considered these nearly typical G. arcuata, though their sulcus remained faint.

Historical gap between Lee Beds 51 and 52: 10 ft (about 3.05 m)
Lee recorded an unexposed interval here. It is retained as a gap, with no invented lithology or fauna.

Lee Bed 52: 20 ft (about 6.10 m)
Micaceous shale containing twelve calcareous sandstone bands.

Lee Bed 53: 1 ft (about 0.30 m)
Calcareous sandstone with a band of very large bivalves recorded under the historical name Lima gigantea.

Lee Bed 54: 5 ft (about 1.52 m)
Calcareous sandstone and sandy shale with Gryphaea arcuata, described by Lee as typical of that species.

Lee Bed 55: 15 ft (about 4.57 m)
Further calcareous sandstone and sandy shale, with conspicuously corrugated Gryphaea shells.

Lee Bed 56: 50 ft (about 15.24 m)
Muddy, calcareous sandstone rich in mica. Lee recorded Gryphaea arcuata, large “bucklandi-type” ammonites around the middle and Vermiceras compared with V. conybeari about 10 ft above the base. These are historical identifications and placements, not a newly established modern ammonite zonation.

Additional historical ammonite horizons near the waterfall
Lee recorded ammonites under the historical name Agassiceras at the foot of the cliff below the waterfall, and Arnioceras several feet below the waterfall lip. These observations are retained as local fossil horizons; their old zonal terminology is not used to impose an unverified modern bed boundary.

Hallaig Sandstone Member

The BGS places this Sinemurian sandstone member at the top of the Ardnish Formation. Some sedimentological papers place it in an enlarged Pabay Shale Formation, a usage not adopted by BGS; the two treatments describe the same rocks. The member is represented in the waterfall-area sandy succession, but the available historic log does not locate its lower boundary precisely. Its regional thickness estimate must not be substituted for an exact thickness exposed at the waterfall. In the BGS unit description, moderately cemented fine- to medium-grained sandstone is described in terms of three interpreted cycles, with bioturbated sandstone and thin siltstone below and cross-stratified sandstone towards the top. The formal lower boundary is unseen, and Pabay Shale locally overlies the member unconformably. These member-scale characteristics are not a claim that three complete cycles can be matched to Lee’s individual beds at Hallaig.

Unnumbered sandstone above Lee Bed 56: 40 ft (about 12.19 m)
Lee described the cliff north of the waterfall as flaggy, carbonaceous sandstone with rusty weathering, ferruginous nodules and abundant trace-like markings. Gryphaea was sparse, concentrated in a layer about 6 ft below its top. His tentative records of Arietites turneri, A. brooki and A. plotti were regarded as indicating the Turneri Zone, but he also listed Microderoceras birchi. Lee explicitly considered the material insufficient to establish the thickness attributable to the old Birchi Zone. Modern GCR accounts assign the top of the Hallaig Sandstone Member here to the Turneri Zone; the historic contrasting record is retained without inventing a precisely located additional boundary.

The relatively strong sandstone forms the platform beneath the landslip. Near the cliff north of the waterfall, around NG 5940 3870, and at the shore scarp farther north, the landslip’s basal surface lies in the overlying weaker Pabay mudrocks. Small remnants of basal Pabay Shale survive in place above the sandstone; the surviving basal Pabay strata are reported as Oxynotum Zone age. This remnant is separate from the much younger upper Pabay sequence measured along the main fossil shore.

Pabay Shale Formation

The formation spans Sinemurian and Pliensbachian time regionally. At Hallaig, the oldest shore exposures are disrupted by landslip movement, whereas the northern measured section preserves approximately 23 m of its upper part. Dark mica-rich shale, silty mudstone and limestone nodules are characteristic. There is no continuous local exposure of a 180 m formation thickness.

Sheared southern Pabay exposures
North of the Hallaig Sandstone scarp, the dark shales are strongly faulted and sheared at the landslip base. Red-weathering calcareous nodules remain conspicuous, but bedding and original thickness are poorly preserved. Echioceras and Eoderoceras identify Raricostatum Zone strata. This material cannot supply a reliable measured succession.

Separate coherent block at NG 5914 3906
A small headland exposes dark-grey to black micaceous shale and nodules dipping about 40° west-south-west. It is a separately rotated landslip block and has no demonstrated bed-by-bed continuity with the main section to the north. Fossils include Polymorphites cf. angusta, eoderoceratids and echioceratids; bivalves include Gryphaea mccullochi, Hippopodium ponderosum and Pleuromya costata, with the brachiopods Spiriferina pinguis and Rimirhynchia anglica. Raricostatum and Jamesoni faunas may both be present, but the Sinemurian–Pliensbachian boundary has not been fixed within the block.

Main measured foreshore section. The continuous log runs for roughly 400 m from NG 5904 3916 to NG 5888 3958, with beds dipping close to 30° west. Howarth’s bed numbers are used below, following the GCR account and its later ammonite revisions. Its structural continuity is internal to this section; it does not bridge the break to the southern headland.

Howarth Bed 1
Dark-grey, micaceous, slightly silty shale with limestone nodules that weather reddish. Some nodules formed early, before compaction; others are later, septarian concretions. Uptonia jamesoni and U. angusta occur in the upper part and indicate the Jamesoni Subzone. Platypleuroceras brevispina may come from a slightly lower level, suggesting the Brevispina Subzone. Only the upper part is drawn in the published column; the GCR prose describes the bed as about 12 m thick.

Howarth Bed 2
Micaceous shale contains limestone lenses and nodules with red-weathered surfaces. Acanthopleuroceras and Tragophylloceras loscombi indicate the Valdani Subzone of the Ibex Zone. The Jamesoni–Ibex zonal boundary is placed between Beds 1 and 2, but the position of the intervening Masseanum Subzone cannot be established from diagnostic ammonites.

Howarth Bed 3 (7.62 m)
A 7.62 m interval of mica-rich shale with thin, lens-shaped calcareous sandstones and broken shell debris, mainly bivalves. No ammonites have been identified from it; a Valdani Subzone age is inferred. The published graphic omits 4 m to save space, so its drawn height must not be mistaken for the bed’s measured thickness.

Scalpay Sandstone Formation

The main foreshore log describes the lowest approximately 40 m of this formation. The beds are early Pliensbachian, ranging from the Ibex into the Davoei Zone. Muddy sandstone and silty shale alternate with calcite-cemented beds and doggers; the transition from the underlying Pabay Shale is gradual. “Scalpa Sandstone” is the older spelling. Thicknesses for the complete formation elsewhere on Raasay are not measurements of this shore log.

Howarth Bed 4
Calcareous sandstone with shale. Its first continuous sandstone marks the locally accepted formation base. This is a practical boundary within a gradual upward increase in sand, placed within the Valdani Subzone rather than at an ammonite-zone boundary.

Howarth Bed 5
Sandy shale with a calcareous band near the middle. Nodules yield the brachiopod Piarorhynchia cf. deffneri; Liparoceras cheltiense is also recorded. The interval is assigned to the Valdani Subzone, although this ammonite’s wider range means it does not fix a sharp subzonal boundary.

Howarth Bed 6
Alternating shale and sandstone, part of the predominantly bioturbated lower formation.

Howarth Bed 7
Sandstone with stronger calcareous cementation at both its base and top.

Howarth Bed 8
Muddy sandstone containing calcareous lenses and doggers. The Valdani–Luridum subzonal boundary is placed tentatively within this bed; it is not exposed as a demonstrable time-plane.

Howarth Bed 9
Hard, calcite-cemented sandstone. The brachiopod Tetrarhynchia dunrobinensis provides a useful fossil record above the tentative subzonal boundary.

Howarth Bed 10
Sandstone with sandy shale and calcareous doggers, becoming more silty towards the top. Some parts contain large Gryphaea gigantea. Across Beds 5–10, burrowing is widespread, while recognisable fossils are otherwise relatively uncommon; poorly preserved infaunal bivalves include forms compared with Pholadomya and Pleuromya.

Howarth Bed 11
Sandy to silty shale. Specimens of Beaniceras transitional between B. crassum and B. luridum place this level in the Luridum Subzone of the Ibex Zone. This later interpretation supersedes Howarth’s assignment based on Androgynoceras maculatum.

Howarth Bed 12
Sandstone, partly calcareous, with subordinate shale. The Ibex–Davoei zonal boundary, also the Luridum–Maculatum subzonal boundary, is interpolated within this bed between the ammonites recorded in Beds 11 and 13.

Howarth Bed 13
Muddy and calcareous sandstone with a shale layer, thin cemented beds and doggers. Androgynoceras transitional between A. maculatum and A. sparsicosta identifies the middle part of the Maculatum Subzone.

Howarth Bed 14
Calcareous shale and sandstone at the base of a conspicuous thin-bedded marker interval. Androgynoceras is recorded in this part of the section.

Howarth Bed 15
Fissile, micaceous shale crowded with crushed bivalve shells.

Howarth Bed 16
Sandy shale between the two distinctive shell-rich fissile shale beds.

Howarth Bed 17
A second fissile, mica-rich shale densely packed with crushed bivalves. The published column records Androgynoceras near the upper part of the marker interval.

Howarth Bed 18
Hard calcareous sandstone with conspicuous vertical joints, capping the thin-bedded marker package. Beds 14–18 allow correlation with other Raasay sections, but their precise relationship to the Maculatum–Capricornus subzonal boundary remains uncertain.

Howarth Bed 19
Calcareous sandstone. Aegoceras capricornus from its lower part establishes the Capricornus Subzone of the Davoei Zone.

Higher low-cliff horizons: Howarth Beds 28–30 and 36
Behind the raised-beach platform, the low cliff exposes higher Scalpay Sandstone than the numbered foreshore log above. Near its southern end, dogger-bearing sandstone and shell bands containing Pseudopecten equivalvis correlate with Howarth’s Beds 28–30; much of the massive cliff sandstone corresponds to Bed 36. These identifications are recorded for Hallaig itself. The complete intervening bed-by-bed logs measured at Rubha na Leac or Cadha Carnach are not reproduced here as though they were measured on this shore.

Lobster-bearing loose block in the northern Hallaig landslip
The type specimen of Pseudoglyphea foersteri came from a loose block of bioturbated, mica-rich silty sandstone at NG 5861 4030, north of the core measured shore section. Associated fossils and pyritised wood occur in the block, and Aegoceras cf. brevilobatum supports a Pliensbachian Davoei Zone age. The original bed of the fallen block was not established, so it cannot be inserted as an additional numbered bed in the foreshore succession.

Depositional interpretation of the main shore. Pabay mud accumulated in normal marine water below wave-base. Its abundant mica points to sediment supplied from the nearby eastern hinterland. Sand lenses and fragmented shells in Bed 3 were interpreted as shallow channels associated with a seabed approaching storm wave-base. The overlying Scalpay beds represent a shallower, sandier marine setting with extensive burrowing. Most hard cemented beds and doggers formed during later diagenesis. Driftwood records a land-derived component; it does not make the marine beds a forest deposit.

Landslip and wider geological setting. The main Hallaig landslip repeats and tilts the Jurassic succession above a failure surface in Pabay Shale. Its northern part retains coherent blocks, while the area around the township is more chaotically disrupted. The high inland scarp includes Bearreraig Sandstone; Portree Shale and Raasay Ironstone are inferred beneath it in poorly exposed ground. Younger strata mapped around the upper landslip, including Great Estuarine Group rocks, belong to the wider landscape rather than to the measured fossil foreshore. Raised-beach deposits, slope debris and the dolerite intrusions are younger features that must not be mistaken for additional marine sedimentary beds.

Geological references
Morton, N. (2004). Hallaig Shore. In British Lower Jurassic Stratigraphy, Geological Conservation Review 30, pp. 331–337; especially Figure 8.7.
Morton, N. (1999). Middle Hettangian (Lower Jurassic) ammonites from Isle of Raasay, Inner Hebrides, and correlation of the Hettangian–lowermost Sinemurian Breakish Formation in the Skye area, NW Scotland. Scottish Journal of Geology 35, 119–130; Figure 3.
Lee, G.W. (1920), with palaeontological work by S.S. Buckman. The Mesozoic Rocks of Applecross, Raasay, and North-East Skye. Geological Survey memoir; pp. 12–16 and 21–22.
Howarth, M.K. (1956). The Scalpa Sandstone of the Isle of Raasay, Inner Hebrides. Proceedings of the Yorkshire Geological Society 30, 353–370. Bed numbering as reproduced and updated in the GCR account.
Phelps, M.C. (1985). A refined ammonite biostratigraphy for the Middle and Upper Carixian (Ibex and Davoei Zones, Lower Jurassic) in North-West Europe and stratigraphical details of the Carixian-Domerian boundary. Geobios 18(3), 321–367.
Hesselbo, S.P., Oates, M.J. and Jenkyns, H.C. (1998). The lower Lias Group of the Hebrides Basin. Scottish Journal of Geology 34(1), 23–60.
BGS Lexicon: Hallaig Sandstone Member.
Emeleus, C.H. and Bell, B.R. (2005). British Regional Geology: The Palaeogene Volcanic Districts of Scotland. Jurassic chapter.
Bell, B.R. SE Raasay, Excursion Raasay 5. Formal field-guide account of the southern approach, older bay sections and landslip.
Feldmann, R.M., Crisp, G. and Pirrie, D. (2002). A new species of glypheoid lobster, Pseudoglyphea foersteri (Decapoda: Astacidea: Mecochiridae) from the Lower Jurassic (Pliensbachian) of Raasay, Inner Hebrides, UK. Palaeontology 45, 23–32.
Cooper, R.G. (2007). Hallaig, Isle of Raasay. Mass Movements in Great Britain, Geological Conservation Review 33.