Trace Fossils from Lower Palaeozoic Ocean-Floor Sediments of the Southern Uplands of Scotland M

Transactions of the Royal Society of Edinburgh: Earth Sciences, 73, 67-87, 1982

Trace fossils from Lower Palaeozoic ocean-floor sediments of the Southern Uplands of Scotland M. J. Benton

ABSTRACT: The Ordovician and Silurian rocks of the Southern Uplands of Scotland have been interpreted as sediments deposited on the northern margin of the Iapetus Ocean. Trace fossils are abundant at many localities in ocean-floor turbidites and mudstones that usually lack all other evidence of life. Twelve ichnogenera are present, and they are mainly meandering locomotion and feeding trails and burrow networks: Dictyodora, Caridolites, Helminthoida, Neonereites, Nereites, Protovirgularia, Gordia, Megagrapton, Paleodictyon, Chondrites, Plano- lites and Skolithos. The trace fossils occur in at least five distinct assemblages and the composition of these was probably controlled by the frequency and nature of the turbidity currents, and possibly by the oxygen content of the mudstones. Where turbidity currents were weak, abundant Dictyodora, together with Caridolites, Neonereites, Nereites, Protovirgularia and Gordia occur in various combinations. Where currents were stronger, traces such as Gordia, Paleodictyon and Megagrapton may be exhumed and cast on turbidite soles, and the sand may contain Skolithos. The 'deep-sea' Nereites trace fossil facies is divisible into several assemblages, presumably environmentally controlled.

KEY WORDS: Iapetus Ocean, ichnology, mudstone, Nereites Facies, Ordovician, shale, Silurian, turbidite.

Deep-sea trace fossil assemblages of the Ordovician and 1. Geological setting Silurian are poorly known. The Lower Palaeozoic turbidites and associated mudstones of the Southern Uplands of Scot- 1.1. Structure and history of deposition land preserve at least 12 ichnogenera and there are several The Ordovician and Silurian rocks of the Southern Uplands distinct assemblages that are associated with particular (basalts, cherts, graptolitic shales, greywackes and red or sedimentary conditions. Trace fossils are frequently the only green mudstones) have been interpreted as the deposits of indications of sea-floor life, and associated fossils consist an ancient ocean-floor trench (Walton 1955; Kelling 1964; almost exclusively of graptolites, and even they are absent Ziegler 1970; Dewey 1971; Piper 1972). The assemblage is from'many formations. Dictyodora and associated trace interpreted to have been deposited on the northwestern fossils from the late Llandovery Gala Group have been shore of the ancient Iapetus Ocean that closed during Silur- described by M'Coy (1851a,b), Nicholson (1873, 1978), and ian and Devonian times (Dewey 1971; McKerrow & Ziegler Benton and Trewin (1978, 1980). Other accounts include 1972; Phillips et al. 1976). Recently, it has been proposed Harkness (1855) on trace fossils of late Ordovician age and that the sediments were stripped off the down-going north- Harkness (1856), Hopkinson (1870), and Nicholson and ern Iapetus oceanic plate and accreted to the inner trench Etheridge (1880) on those of late Llandovery age. Peach and wall on the Scottish continental margin (Mitchell & McKer- Home (1899) list many trace fossil localities. row 1975; McKerrow et al. 1977). This accretionary prism Between 1977 and 1981 I collected trace fossils from 48 model derives from the general imbricate nature of the localities which are distributed patchily over the poorly Southern Uplands which are divided into a series of at least exposed outcrop. Specimens from this collection, to which 10 slices (Fig. 1) bounded by major NE-SW-trending reverse reference is made, are now housed in the Royal Scottish strike faults (Leggett et al. 1979). The beds in each sequence Museum (RSM). Museum material was examined in the generally young N, but the sequences as a whole young S. collections of Aberdeen University Geology Department Sequences 1-3 are middle to late Ordovician in age and they (AUGD), Birmingham University Geology Department have been distinguished as the northern belt, sequences 4-9 Museum, Lapworth Collection (BU), British Museum, (Llandovery) as the central belt, and sequence 10 (late Natural History, Gray collection etc. (BMNH), Geological Llandovery-Wenlock) as the southern belt. Survey, Edinburgh, Macconochie, and Peach and Home Several phases of deposition are recognisable in the South- Collections (GSE), Geological Survey Museum, London ern Uplands, but exact dating of the sequences is difficult (GSM), Hawick Museum (HaM), Hunterian Museum, Glas- because of limited fauna, except for graptolites in the black gow University (HM), and Sedgwick Museum, Cambridge shales. The earliest turbidites (? late Llandeilo-early Cara- University (SM). doc) are rich in ophiolitic debris and are probably trench The aims of this paper are to review the trace fossils of the deposits (Leggett 1980). Caradoc black shales (Glenkiln and deep-water greywacke-mudstone facies of the Southern Up- Hartfell shales) are overlain by further Caradoc-earliest lands and to give some preliminary remarks on their en- Llandovery (?) greywackes in the northern belt which prob- vironmental significance. ably had a similar trench depositional origin. In the central Trac e fossi l assemblage s

Dictyodors scotica £s 5 Protovirgularia

2 D. scotica/ Gordia Q SGordia/Pateodic

Skolithos

5° W

Figure 1 Geological map of the Southern Uplands of Scotland; major reverse faults are marked (based on Geological Survey maps and Oliver & Leggett (1980)) and distinct stratigraphic sequences of the accretionary prism model are numbered 1-10 (Leggett et al. 1979). The sequences as a whole generally young SE, while beds within each tract young mainly NW. Trace fossil localities are numbered 1-48 (details and grid references in section 4 and Table 1) . Symbols indicate trace fossil assemblages at each locality (described in section 3.1 and Figs 12, 13). TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 69 belt, pelagic black shales were deposited during late Ordovi- The sediments in certain slices (e.g. 9) may be correlated cian and early Llandovery times (Glenkiln, Hartfell, Birkhill along strike, but most others are well defined only in places. shales) and turbidite deposition started in the middle to late In some cases there is extensive lateral variation within slices Llandovery. The late Llandovery and Wenlock greywackes (e.g. 5-8 in the region from Moffat to St Mary's Loch cannot become quartz-rich and they were probably ocean-floor- be traced eastwards into the Galashiels and Berwickshire abyssal plain deposits (Leggett 1980). Trace fossils are most areas). Thus, the stratigraphy is mainly local in application abundant in these later oceanic sediments and occur only and only a few details relevant to the trace fossil-bearing rarely in the Ordovician. beds are given here. The Ordovician trace fossils of Stobo and Coulter Craigs 1.2. Stratigraphy and sedimentology (Fig. 1; section 4) occur generally on the bases of fine- The stratigraphy of the turbidite sequences is complex be- grained blue-grey greywackes of the Lowther Beds cause of the imbricate structure of the Southern Uplands. (Ashgill?) (Leggett 1980). The specimens from Barlaes

Table 1 Trace fossil localities of the Southern Uplands of Scotland LOCALITY TRACE FOSSILS LITHOLOGIES ASSEMBLAGES otica

eayi .a

B ei a e l la n g d e sol e mad •§ e o cambrensi. tenuis pugnus jacksoni Nereites Caridolites Helminthoida N. Neonereites Protovirgular, D. N. Skolithos grey-gree mudston Gordia Megagrapton Chondrites Planolites purple-re turbidit mudston 3 N. Paleodictyon

1 Stobo Slate Qu. X X X X X 6, 7 2 Coulter Craigs X X 6 3 Barlaes X X X X X X X X X 1, 6 4 Old Cambus X X X X 1 5 Ellemford X? X 1? 6 Heron's Hole X X X 7 Wedderlie Farm X X X X 8 Bruntaburn X X X? X X 9 Blythe Water Qu. X X X X? X X 10 Earnscleugh Burn X X X ! 11 Blackcock Plantation X X X X 12 Avenel X X X 13 Westerhill X X 14 Buckholm Hill X X X 15 Ladhope Burn X X 16 The Whin X X X 17 Caddonfoot X X 18 Caddonlee X X 19 Meigle X X 20 Newhall Farm X X 21 Ferniehirst X X X 22 Caddonhead X X 23 Thornylee X X X X X X X X X 7 24 Holylee X X X X 25 Grieston Qu. X X X 3 26 Hunter Hill X X X 6 27 Dobb's Linn X X X X 6? 28 Craigmichan Scaurs X X X X 6 29 Hunterheck Hill X X X X X X X X X 4, 6 30 Glenjorrie Qu. X X X 6 31 Garrochtrie X X X 3 32 Penwhapple Glen X X X X X X X X X X X X X 1, 5, 6 33 Eyemouth X X 6 34 Bowden Burn X X 6 35 Selkirk Common X X X 1? 36 Greenhill Qu. X X X X X 1, 5 37 Stirches Qu. X X X X X X X 4, 6, 7 38 Adderstonlee X X 6 39 Binks X X X X 6, 7 40 Halketleaths X X 5 41 Castle Douglas X X 5 42 Torrs Point X X 5 43 Mull Point X X X 6 44 Garliestown Bay X X 5 45 Palmallet Point X X 7 46 Stobs Castle Qu. X X X 6 47 Yadd Linn X X X X X 4, 6,7 48 Lockerbie X X

Explanation of Table 1 Localities 1-3 Ordovician, 4-31 Gala Group (late Llandovery), 32 Penkill Group (late Llandovery), 33-45 Hawick Rocks (late Llandovery?), 46-48 Riccarton Group (Wenlock); locality details are listed in section 4 and assemblages are reviewed in section 3.1 and in Figures 11, 12. 70 M. J. BENTON Quarry (Ashgill?) occur within grey-green laminated mud- turbidite soles. stone and siltstone and as sole-marks on fine turbidite sand- A distinctive assemblage of trace fossils occurs on fine stone units of the Shinnel Group (Peach & Home 1899, pp. turbidite soles at some localities in the Hawick rocks (Fig. 383-4). 1-sequence 9) running NE-SW from Melrose and Hawick to The unit richest in trace fossils is the Gala Group of Kirkudbright and Whithorn. The unit is a turbidite sequence Lapworth (1870), or Queensberry Group of Peach & Home consisting of fine-grained flaggy sandstone, siltstone, and (1899) (late Llandovery, ? turriculatus-crenulata zones— mudstone greywacke and red mudstone interbeds (Lapworth Toghill & Strachan 1970). This group, and its lateral equiva- 1889; Peach & Home 1899; Warren 1964). The age is lents, occurs from Berwickshire, through Galashiels and uncertain because of the general lack of fossils and it is Moffat, to Wigtown and Galloway in sequences 4-8 of the currently regarded as Upper Llandovery (Rust 1965a; Leg- central belt. The turbidites consist of blue-grey or green fine gett et al. 1979), Wenlock (Warren 1964), or Ludlow (Clark- to medium-grained sandstone, often with small to large tool son et al. 1975). marks on the soles, and occur in units varying from a few Similar trace fossils occur as sole casts in the Stobs Castle centimetres to 5 m in thickness. Trace fossils occur in the Beds (? late Llandovery-early Wenlock, murchisoni Zone— interbedded fine-grained units and more abundantly in the Warren 1964) and Shankend Beds (early Wenlock: murchi- purple and red rather than the green and grey shales (Ben- soni—riccartonensis zones—Warren 1964) of the Riccarton ton & Trewin 1980). Group. The sediments consist of mudstone to fine-grained In the Girvan area, the Penkill Formation and the Pro- greywackes, red mudstones, and graptolitic shales in the tovirgularia Grits (Upper Llandovery; turriculatus and gries- former, and mudstone to coarse-grained greywackes and toniensis zones respectively—Cocks & Toghill 1973) are graptolitic shales in the latter (Warren 1964). similar to the Gala Group in sedimentology and fossil con- The localities are listed in section 4 and a summary of tent. Trace fossils are abundant in the purple mudstones of trace fossils, lithologies and assemblage types is given in the Penkill Formation and less so in the green beds and in the Table 1. Protovirgularia Grits where traces are often preserved on

~««ss;

Figure 2 Dictyodora from the Gala Group (Upper Llandovery). (a) D. scotica, basal burrow, bedding plane view showing close packing and turning circle; Thornylee; AUGD 10723; x 0-8. (b) D. scotica, vertical polished section showing typical cross-section of basal burrow and mid-dorsal vertical wall in red and grey-green laminated shale; Blackcock; RSM 1981.30.51; x 1-3. (c) D. scotica, vertically broken slab showing wall and striation pattern; Ferniehirst; GSE 13742; x 1-0. (d) D. scotica, bedding plane section across vertical walls of at least two overlapping specimens; Thornylee; RSM 1981.30.64; x 0-8. (e) D. tenuis, bedding plane view of section across wall showing secondary sinuosity; Grieston; AUGD 10716; x 1-6. TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 71 2. Trace fossil descriptions Table 2 Characters of Dictyodora specimens measured [or the multivariate analysis; definitions illustrated in Figure 3 2.1. Ichnogenus Dictyodora Weiss 1884 1 Secondary looping, presence 7 Vertical wall height. The ichnogenus Dictyodora has been described under a or absence. 8 Minimum radius of curva- 2 Minimum loop length. ture of turn. variety of names from the southern Uplands, including 3 Maximum loop length. 9 Maximum radius of curva- Crossopodia scotica M'Coy 1851 and Myrianites tenuis 4 Minimum loop width. ture of turn. M'Coy 1851. 5 Maximum loop width. 10 Regular looping, presence or Dictyodora scotica (M'Coy 1851) 6 Basal burrow width. absence. (Fig. 2a-d) 1980 Dictyodora scotica (M'Coy): Benton & Trewin, p. 503. Multivariate analysis of Dictyodora. Many specimens of Discussion. This common form (basal burrow 1-5- Dictyodora have been collected in the Upper Ordovician and 6-0 mm wide, mid-dorsal vertical wall up to 14 mm high, Upper Llandovery of the Southern Uplands. In order to test forming regular meanders) has been described in detail from the specific unity of D. scotica through this broad spatial and the Gala Group by Benton and Trewin (1980). Some charac- temporal distribution and its separation from D. tenuis, a teristic bedding plane views and vertical views of basal series of characters (Table 2) was measured from 86 speci- burrow and wall are shown in Figure 2a-d. The Upper mens. The characters are a mixture of continuously variable Ordovician material from Barlaes differs little from the late and binary traits, and they were combined in a principal Llandovery D. scotica, although the loops are sometimes components analysis (PCA). The data were standardized to longer (up to 90 mm). unit means and zero standard deviations and used in Pro- Occurrence. D. scotica is the commonest trace fossil at gram BMDP4M (UCLA 1975) on the Numac IBM 370/168 the typical Gala Group localities: Thornylee, Bruntaburn, computer. PCA summarises variation between specimens in Blythe, Blackcock, Buckholm Mill, Holylee. It is also the a reduced number of axes and the first two axes represent commonest trace fossil in the "Crossopodia Shales" of the most discrimination. Two-dimensional scatter diagrams are Penkill Group in Penwhapple Glen, Girvan, and is abundant plotted and the degree of affinity is indicated by the close- in the Upper Ordovician of Barlaes Quarry. Very similar ness of points in the plots. material has been reported from the Longford-Down massif The results, plotted against the first two reduced axes, are of Co. Down (Doughty 1980). given in Figure 3. There is a separation between two groups, although it is not large and cannot mean more than a specific Dictyodora tenuis (M'Coy 1851) distinction. One large diffuse cluster corresponds to D. (Fig. 2e) scotica, while the smaller cluster is composed solely of 1980 Dictyodora tenuis (M'Coy); Benton & Trewin, p. 507. material of D. tenuis from Grieston. The Ordovician speci- Discussion. This small irregular Dictyodora (basal burrow mens from Barlaes fall well within the D. scotica cluster. 1-0—3-0 mm wide, wall less than 10 mm high, secondary This analysis confirms that D. scotica is a highly variable sinuosity) has been redescribed recently by Benton and trace fossil (as suggested by Benton & Trewin 1980), but it is Trewin (1980) and a typical bedding plane view is shown in always distinguishable from D. tenuis in the Southern Up- Figure 2e. lands. Occurrence. D. tenuis occurs associated with D. scotica in 2.2. Ichnogenus Caridolites Etheridge, Woodward & many Gala Group localities, such as Thornylee, Holylee, and in Gala Group equivalents at Garrochtrie. It is the Jones 1890 dominant form at Grieston; it is also common in the "Crosso- podia Shales" of the Penkill Group of Penwhapple, Girvan. Caridolites wilsoni Etheridge, Woodward & Jones 1890 (Fig. 4a) 71855 Trichoides ambiguus Harkness (partim), pp. 474-5. 71870 Trichoides ambiguus Harkness; Hopkinson, pp. 78, 79. 71870 Trichoides ambiguus Harkness; Lapworth, p. 54. vl873 Caridolites wilsoni Nicholson, pp. 289, 290 (nom. nud.). v*1890 Caridolites (Ceratiocaris?) wilsoni Nicholson; Ether- idge, Woodward & Jones, p. 65. 1969 Caridolites Nicholson; Rolfe, p. R330 ("Phyllocarida inc. sed.") 1975 Caridolites Nicholson; Hantzschel, p. W182 ("Un- recognized and unrecognizable genera" of trace fossils). vl980 Caridolites wilsoni Etheridge, Woodward & Jones; Benton and Trewin, pp. 510-1, fig. 6, 7. Lectotype. Here designated, AUGD 7059, the original of Nicholson (1873, 1978) and Etheridge, Woodward and Jones factor 1 (1890), Gala Group, Grieston Quarry. Figure 3 Multivariate analysis of Scottish Dictyodora; scatter dia- Other material. AUGD 7055, 10674-5, 10723, 10748 gram from principal components analysis of 86 specimens plotted from Grieston; BMNH A6174; RSM 1981.30.75 from Pen- against first two factors; discrimination represented by x axis is whapple; GSE uncat. from Caddonfoot and Ferniehirst; 42-3%, and y axis 18-4%; characters measured are shown and listed RSM 1896.24.11 from Garrochtrie; RSM 1982.57.1, in Table 1; D. tenuis separates from D. scotica. Localities ( 3 Barlaes, Q Penwhapple, A Thornylee and other Gala Group 1981.30.4,6-8,10 from Barlaes. localities (Old Cambus, Longformacus, Bruntaburn, Blythe, Black- Description. Burrows about 1 mm wide and up to 5 mm cock, Buckholm), Q Grieston. deep with expanded basal portion. Traces run in straight 72 M. J. BENTON lines, 10-100 mm long, and they may cross. The top view on other. This species has been assigned to Gordia by Ksiaz- a bedding plane gives the superficial appearance of small kiewicz (1977, p. 156), but the latter genus should show no tool marks (Fig. 4a). regular looping at all (Emmons 1844, pi. 2). Seilacher (1967, Discussion. Trichoides ambiguus Harkness 1855 was de- p. 76) described a zone of disturbance created by churning of scribed as "hair-like bodies, generally straight, but some- sediment on either side of the trace, as seen in this form. times having a slight curve". Some showed "apparent bran- There is no evidence of any connection between this kind of ching" and "serratures ... on their side". The original trace and Dictyodora although the bedding plane meander- material is not known, but some of the specimens probably ing patterns may seem similar. belong to Caridolites and others to Gordia. The name Trichoides is best not revived. Hantzschel (1975, p. W189) assigns it to "unrecognized and unrecognizable genera". Nicholson (1873) mentioned the name Caridolites wilsoni, but the first brief account was given by Etheridge, Wood- ward and Jones (1890), and this must rank as the type description. Nicholson's 1873 paper was an abstract of a longer monograph that has only recently been published (Nicholson 1978). The name Caridolites has not been used recently because of the brief descriptions available, but apparently no other name has been proposed since for such small straight burrows. Occurrence. Caridolites is common at Grieston and occurs at all typical Gala Group localities, such as Brunta- f burn, Blythe, Earnscleugh, Blackcock, Buckholm Mill, Cad- donfoot, Ferniehirst and Thornylee, as well as Garrochtrie, ** and the Penkill Group of Penwhapple, Girvan. It also occurs in the Upper Ordovician of Barlaes Quarry and the Hawick Rocks of Stirches. Usually associated with Dictyodora. a 2.3. Ichnogenus Helminthoida Schafhautl 1851 Some specimens from the Southern Uplands appear to belong to Helminthoida, an ichnogenus typical of Cretaceous and Tertiary flysch, although it occurs earlier. Palaeohelmin- thoida Ruchholz 1967 from the Upper Devonian of Germany is very similar. It supposedly differs in the "very narrow, cordlike ridge and by close contact of meanders" (Hant- zschel 1975, p. W87). However, the meanders of Helmin- thoida are often closer, and it is likely that Palaeohelmin- thoida should be included in Helminthoida. Our material consists of a small and a large form. Helminthoida cf. labyrinthica Heer 1865 (Fig. 4b) Material. RSM 1981.30.96 from Stirches. Description. Regularly meandering tunnel trace, 0-2- 0-3 mm wide, loops spaced 2-3 mm apart. Discussion. This small form closely matches in size and pattern a specimen of H. labyrinthica figured by Ksiaz- kiewicz (1970, fig. 2g) from the Paleocene of Poland. It could also be referred to H. (Helminthorhaphe) crassa which has rather less closely spaced burrows (Ksiazkiewicz 1977; Seilacher 1977). Occurrence. Grey-green laminated mudstones of the Hawick Rocks at Stirches. Helminthoida (?) molassica Heer 1865 (Fig. 4c) Material. RSM 1981.30.71 from Hunterheck; RSM 1981.30.97 from Stirches. Description. Meandering tunnel trace of uniform width (1 mm), forming loose loops (50-100 mm long, 5-20 mm across). Generally restricted to one mudstone lamina, but •£ other tracks at a slightly different level may seem to cut the trace. Bounded by a diffuse lateral zone (total width 10- Figure 4 (a) Caridolites, bedding plane view showing numerous examples; 15 mm) of "smoothed" or churned sediment. There is no Upper Llandovery, Grieston; AUGD 10674; x 1-0. sign at all of a vertical wall. (b) Helminthoida, small form, bedding plane view showing part of Discussion. This large form resembles a specimen figured regular looping pattern; Upper Llandovery, Stirches; as H. (?) aff. molassica by Ksiazkiewicz (1970, fig. 2j) which RSM 1981.30.96; x 1-5. (c) Helminthoida, large form, bedding plane view showing irregular appears to differ from H. labyrinthica only in that it is less looping and overlapping traces; Upper Llandovery, Stirches; regular in pattern and that burrows may appear to cut each RSM 1981.30.97; x 0-8. TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 73 Occurrence. Grey-green laminated mudstones of the specimen from Holylee (Fig. 5d) shows a looped trail of over Hawick Rocks at Stirches. Obscure traces, probably Helmin- 100 tiny circular blobs, each about 0-7-1-0 mm in diameter, thoida, occur poorly preserved in purple fine-grained sand- and preserved as convex epireliefs. Similar specimens from stone at Hunterheck. Thornylee (SM A45581) consist of concave impressions of beads. In all specimens the beads alternate fairly regularly 2.4. Ichnogenus Neonereites Seilacher 1960 and the two rows are closely united. Larger specimens with similar irregular looping double trails of oval beads, 2-3 mm Neonereites uniserialis Seilacher 1960 diameter, occur at Greenhill (Fig. 5e) and and Barlaes Quarry. (Fig. 5a-c) Discussion. Nereites multiforis Harkness 1855 from Bar- 71870 Dexolites gracilis Hopkinson, pp. 77-78, fig. 1. laes Quarry was described as "a double row of small pits, vl880 Eione (?) sp. ind., Nicholson & Etheridge, p. 309, pi. generally oval in form, and arranged alternately .... The 24, fig. 4 . greatest width of the pits does not exceed l/5th of an inch", 1960 Neonereites uniserialis Seilacher, p. 48, fig. 3, pi. 2, these specimens almost certainly do not belong to Nereites, fig. 1. but the original specimens are unknown, and the name has Material. HM X1003/6 from Thornylee; GSE M4585a, not been used since 1855. 4586a, 4599a from Buckholm Mill; RSM 1896.24.6-7, 10 from Longformacus; BMNH A6175, A6178-81, A6187-8 Occurrence. Typical Gala Group localities like Thornylee from Penwhapple: RSM 1981.30.2 from Barlaes; RSM and Holylee, Penkill Group of Penwhapple, Hawick Rocks 1981.30.41, 43-6 from Blythe; RSM 1981.30.58 from of Greenhill Quarry, Upper Ordovician of Barlaes Quarry. Grieston. Description. The Southern Uplands N. uniserialis occurs 2.5. Ichnogenus Nereites Macleay 1839 in two forms: single chains of small (0-5-3-0 mm diameter) Many species of Nereites have been recorded from the touching circular impressions, or series of larger (2-6 mm) Lower Palaeozoic. Re-examination of the original material isolated circular to elliptical marks. The impressions are of some of these, and further collections from the Llandov- preserved as positive or negative epireliefs on bed tops, ery of Wales (Macleay in Murchison 1839) and Maine, USA showing that the segments are spheroidal. Specimens from (Emmons 1844) suggests that there are probably only four Penwhapple (e.g. BMNH A6180, Nicholson & Etheridge species present. These may be distinguished readily on the 1880, pi. 24, fig. 4) are of the first type and show series of basis of size and shape of the lateral lobes as follows (Fig. small spheres in straight and curving lines, but the separate 6f): units do not always touch closely. A specimen from Blythe lobe lobe (Fig. 5a) is a trail of about 10 raised circular segments lobes/cm length (mm) shape overlapping. Each segment is 3-0 mm wide and the overlap N. macleayi (Murchison 1839) 6-12 1-2 rounded is about 1 mm. The rest of the slab contains short stretches N. cambrensis Murchison 1839 3-6 2-5 pointed and confused masses of similar blobs, both concave and N. jacksoni Emmons 1844 1-3 5-10 rounded convex epireliefs. One remarkable specimen from Grieston N. pugnus Emmons 1844 2-4 5-10 pointed (Fig. 5b,c) shows 10 stretches of N. uniserialis, each consisting of 10-25 circular blobs varying from 1-5 to 4-0 mm in The Southern Uplands material is rare, but it shows a clear diameter. The beads are all in close contact in a chain, and separation into these four forms. the smaller ones are found towards the ends, giving each trace the appearance of a short stretch of rope, tapering in both directions. Each trace is draped round the front of a Nereites macleayi (Murchison 1839) transverse scour mould of the type described by Dzufyriski (Fig. 6a) and Walton (1965, p. 56, fig. 41). v*1839 Myrianites macleayi Murchison, p. 700, pi. 27, fig. 3. Discussion. Dexolites gracilis Hopkinson 1870 from Hun- 1880 Nereites sp. ind., Nicholson & Etheridge, p. 305, pi. terheck is hard to interpret from the original description, but 23, fig. 1. it may be a specimen of N. uniserialis. The material de- Material. BMNH 58250 (1-5); BU unnumb. from Thor- scribed as Eione (?) sp. ind. by Nicholson and Etheridge nylee; GSEB4084E from Old Cambus Quarry; (1880) also belongs to N. uniserialis since the trace fossil BMNH 58159 (1, 2) from Hunterheck; BMNH A6182; name Eione Tate 1859 is preoccupied by the gastropod name RSM 1981.30.79, 80 from Penwhapple. Eione Rafinesque 1814. Description. Most specimens of N. macleayi are poorly Occurrence. Occurs occasionally in typical Gala Group preserved and allow little more than the counting of the localities, such as Blythe, Buckholm Mill, Thornylee, Gries- blurred lateral lobes. One specimen of BMNH 58250 shows ton and Longformacus, as well as in the Penkill Group of a faint small Nereites with six lobes per cm and each lobe is Penwhapple. about 2 mm long. Other material (e.g. BMNH 58159) shows only the unadorned undertrace in parts. Discussion. The size and regular looping pattern in many Neonereites biserialis Seilacher 1960 examples, especially from Penwhapple, tends to confirm the (Fig. 5d,e) suggestion (Benton & Trewin 1980, p. 511) that small Nere- 71855 Nereites multiforis Harkness, p. 476. ites may be made by the D. tenuis or D. scotica animal, and 1960 Neonereites biserialis Seilacher, pp. 48, 49, fig. 3, pi. the side pattern may represent different behaviour or differ- 2, fig. 2. ent preservation. The specimen figured by Nicholson and 1980 Neonereites biserialis Seilacher; Doughty, p. 100, pi. Etheridge (1880, pi. 23, fig. 1), and mentioned by Lapworth 5, fig. 1,3- (1882, p. 652), as Nereites cambrensis fits i n the size range of Material. SM A45581 from Thornylee; RSM 1981.30.56 N. macleayi. from Holylee; RSM 1981.30.86, 87 from Greenhill. Occurrence. Rare in some Gala Group localities; com- Description. N. biserialis consists of double chains of moner in purple mudstones of the Penkill Formation, beads, and in our material these are often small. One Penkill. 74 M. J. BENTON

Figure 5 Neonereites from the Upper Llandovery. (a) M uniserialis, short stretch; Blythe; RSM 1981.30.43; x 1-5. (b) N. uniserialis clinging to backs of linguoid scour casts on sole of fine sandstone turbidite; Grieston; RSM 1981.30.58; x 0-4. (c) Detail of (b); x 3-0. (d) N. biserialis, small form, looping string of pellets on bedding plane; Holylee; RSM 1981.30.56; x 3-0. (e) N. biserialis, large form, short stretches of oval pellets on bedding plane; Greenhill; RSM 1981.30.87; x 0-8. r TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 75

•»PMS

' 1-&- ''.-**:>

Figure 6 Nereites. (a) /V. madeayi, series of loops showing blurred lobes; Upper Llandovery, Thornylee; BMNH 58250; x 1-0. (b) N. cambrensis, several loops showing pointed leaf-shaped lobes; Upper Llandovery Hunterheck- BMNH 58159; x 1-0. (c) N. jacksoni, two obscure specimens showing large rounded lobes; Upper Llandovery Thornylee- RSM 1981.30.67; x 1-8. (d) N. pugnus, showing well preserved large lobes on fine sandstone turbidite sole; Lower Wenlock Yadd Linn; BMNH 58200; x 0-8. (e) N. pugnus, showing specimens of various sizes; Lower Wenlock, Yadd Linn; BMNH 58200; x 1-0. (f) Nereites identification; diagrams of the four species from the Southern Uplands 1 N. madeayi, 2 N. cambrensis, 3 N. jacksoni, 4 N. pugnus; x 1 -0. 76 M. J. BENTON Nereites cambrensis Murchison 1839 (Fig. 6b) v*1839 Nereites cambrensis Murchison, p. 700, pi. 27, fig. 1. 1851b Nereites cambrensis Murchison, var. a; M'Coy, p. 129. Material. BMNH 58250 ("IX"); SM A45580 from Thor- nylee; BMNH 58159(1-3); GSM IV6/18 from Hunterheck; RSM 1982.57.2 from Barlaes Hill. Description. TV. cambrensis is represented by some good specimens. BMNH 58159 contains one specimen showing well the pointed leaf-like lobes with a central streak. The lobes are 3-6 mm long and there are approximately 3 per cm. SM A45580 also has 3-6 mm lobes and 3-4 per cm. These compare well with the specimens from Wales and Maine. Occurrence. Rare in Gala Group localities (e.g. Thorn- ylee, Hunterheck) and Upper Ordovician of Barlaes. a Nereites jacksoni Emmons 1844 (Fig. 6c) 1844 Nereites jacksoni Emmons, p. 25, 52, pi. 3, fig. 1. Material. BMNH 58159 from Hunterheck; RSM 1981.30.67 from Thornylee. Description. N. jacksoni is represented by good specimens from Hunterheck (BMNH 58159) which shows two series of rounded lateral lobes, each 4-6 mm long, and just over 2 per cm, on either side of a 3 mm wide central strip, the whole trace is about 13 mm wide. The Thornylee specimen (Fig. 6c) shows two short stretches of track with two round lobes per cm, each lobe is 5 mm wide and total track width is 14-15 mm. Occurrence. Rare in Gala Group localities (Thornylee, Hunterheck). Nereites pugnus Emmons 1844 (Fig. 6d,e) 1844 Nereites pugnus Emmons, p. 25, 52, pi. 3, fig. 2; pi. 4, fig. 4. Material. GSM 104244 from Hunterheck; BMNH 58200 from Yadd Linn; RSM 1981.30.105 from Stirches. Description. Large Nereites with total width of 1-3- 2-0 cm, consisting of two series of leaf-shaped lateral lobes, each 7-8 mm long, branching regularly on either side of a 2 mm broad central strip. There are 3-3j lobes per cm. The lobes are sometimes directed more sideways than in the type N. pugnus from Maine. Whole bedding planes may be cov- ered with broad looping specimens of this trace fossil (Fig. 5d,e). Discussion. GSM 104244 shows specimens of N. jacksoni and N. pugnus associated, and it is possible that the two are different preservational aspects of a trace produced by the same animal, and this is suggested also by their similar size. However, the shapes are always distinguishable, and the two names are probably valid. Occurrence. Rare in the Gala Group of Hunterheck, the Hawick Rocks of Stirches, and the Stobs Castle Beds (Ric- carton Group) of Yadd Linn.

2.6. Ichnogenus Protovirgularia M'Coy 1850 Protovirgularia dichotoma M'Coy 1850 (Fig. 7) Figure 7 Protovirgularia dichotoma. (a) Lectotype, SM A45582, showing four specimens; Lower Wen- v*1850 Protovirgularia dichotoma M'Coy, pp. 272-3. lock, Lockerbie; x 1-0. vl851b Protovirgularia dichotoma M'Coy; M'Coy, p. 10, pi. (b) Larger specimen showing variable preservation and change of IB, fig. 11,12. direction; Upper Ordovician, Barlaes; RSM 1981.30.3; x 1-0. 1853 (?) Cladograpsus nereitarum Richter, p. 450, pi. 12, (c) Large specimen showing X-shaped chevrons; Upper Llandov- fig. 1,2. ery, Stirches; RSM 1981.30.94; x 2-1. TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 77 1855 Protovirgularia dichotoma M'Coy; Harkness, p. 475. Riccarton Group. The age assignment was given as Bala by 1855 Protovirgularia dichotoma M'Coy; Murchison & M'Coy (1851b, p. 366) and "Schiefern des Ober- Morris, p. 413. Ordoviziums (Bala beds)" by Hantzschel (1958, p. 84) and 1856 Protovirgularia M'Coy; Harkness, pp. 244-5. this mistake was repeated in the Treatise (Hantzschel 1975, 1870 Protovirgularia harknessi Lapworth, pp. 53, 54 p. W97). (nom. nud.). Protovirgularia has been reported from many other locali- 1871 Protovirgularia M'Coy; Lapworth & Wilson, p. 458. ties in the Southern Uplands, including Barlaes (Harkness 1871 Triplograpsus nereitarum (Richter); Richter, pp. 1855, p. 475), Queensberry Group sites (Lapworth & Wilson 251-2, pi. 5, fig. 10-13. 1871), and locations in the western outcrop of the Hawick 1879 Provirgularia (?) nereitarum (Richter); Giimbel, pp. Rocks (Peach & Home 1899, p. 213, 215, 216). P. harknessi 469, 471, figs 11, 12 (nom. null.). was mentioned by Lapworth (1870) from localities in the 1882 Protovirgularia M'Coy; Lapworth, pp. 652, 660. Gala Group, but has never been described of figured, and is 1889 Protovirgularia M'Coy; Lapworth, table 2 (pp. 67- almost certainly P. dichotoma. 8). German specimens from the Middle Devonian of Thurin- 1899 Protovirgularia harknessi Lapworth; Peach & gia were originally interpreted as graptolites (Richter 1853, Home, pp. 213, 215, 216, 545 (nom. null.). p. 450; 1871, p. 251). Murchison and Morris (1855) and 1931 Protovirgularia nereitarum (Richter); Hundt, p. 35, Giimbel (1879) correctly ascribed this material to Protovir- fig. 1-3; p. 48, fig. 1, 2. gularia, and later works (Hundt 1931; Richter 1941; Hant- 1941 "Ahren-formige Fahrten (Ichnia spicea)", Richter, zschel 1958; Volk 1961; Pfeiffer 1968) confirmed this. The pp. 228-31, fig. 4-6. German material of P. nereitarum is indistinguishable from 1955 Protovirgularia M'Coy; Bulman, p. V95. P. dichotoma, and the two species are synonymised here. 1958 Protovirgularia M'Coy; Hantzschel, p. 84, fig. 5. Sedimentary structures very similar to Protovirgularia 1960 Triplograpsus nereitarum (Richter); Pfeiffer, p. 36, from the Southern Uplands have been named chevron marks fig. 7a. by Craig and Walton (1962, pp. 109-10, fig. 5, pp. VA) and 1961 Protovirgularia nereitarum (Richter); Volk, pp. 69- Dzufyriski and Walton (1965, pp. 103-7,110, figs 6 8 , 74, 93B). 75, pi. 1, 2. These have been produced experimentally by causing a tool 1965 Protovirgularia ? sp. H, Claus, pp. 187-91, pi. 18. to travel over cohesive mud without breaking the surface. 1968 Protovirgularia nereitarum (Richter); Pfeiffer, p. V-shaped ruffles are formed by eddy currents behind the 667, pi. 1, figs 6-8. skimming tool and these point downstream. A range of 1970 Protovirgularia M'Coy; Bulman, p. V139. forms is produced dependent on shape and speed of tool, 1973 Protovirgularia M'Coy; Cocks & Toghill, p. 228. depth of penetration, plasticity of sediment, and grain size. 1975 Protovirgularia M'Coy; Hantzschel, pp. W97-8, figs The forms are grooves without chevrons, grooves with chev- 61,2. rons, V-shaped chevrons without groove, and U-shaped Lectotype. Designated here, SM A45582, the original of chevrons. The V-shaped chevrons resemble Protovirgularia M'Coy (1851b, pi. IB, fig. 11, lla), Riccarton Group (Wen- closely, and some Protovirgularia specimens might be chev- lock) of Lockerbie, near Dumfries. Not "Bala Beds, Upper ron marks, although this was not suggested in either of the Ordovician" as quoted by M'Coy (1851b, p. 366) and Hant- papers cited. However, the trace fossil nature of most Pro- zschel (1958, p. 84; 1975, p. W97). Figured here, Fig. 7a. tovirgularia is suggested by the following: (1) they do not Paralectotypes. SM A45583 (M'Coy, 1851b, pi. IB, fig. show gradations into forms with central grooves or into 12, 12a), A45584; details as for lectotype. U-shaped chevrons, as occurs in true chevron marks, (2) Other material. BMNH A6175 from Penwhapple; BU un- specimens usually occur on surfaces otherwise unaffected by numb. from Ashiesteel Hill, near Thornylee; current activity (ie. not associated with tool marks or scour RSM 1981.30.3 from Barlaes; RSM 1981.30.88 from marks), (3) they may curve and be directed at various angles Greenhill; RSM 1981.30.94, 95 from Stirches. on a single bedding plane, (4) they occur with trace fossils Description. Series of V-shapes or chevrons forming like Dictyodora and Nereites within mudstone sequences, traces 10-100 mm long, 1-7 mm wide. The chevrons are and (5) they show a narrow size range in any formation (tool bilaterally symmetrical, the arms are at an angle of 45-90° to marks would probably show a range of sizes). each other, and there may be between 3 and 20 chevrons per It has been suggested that Protovirgularia was produced cm. When a complete specimen is preserved, the chevrons by a crab (Giimbel 1879), arthropod (Richter 1941; Volk often become smaller towards the ends, producing a tapering 1961), or annelid (Richter 1941; Claus 1965). If the marks effect. The type specimens are 1-0-2 0 mm wide and there represent the scratches of legs or parapodia, rather than are 8-10 chevrons per cm. Some of the traces overlap and eddy marks produced by the movement of an animal over M'Coy mistakenly interpreted this as dichotomous branching the surface, it is hard to visualise the kind of limb motions (hence the species name). The chevron pattern has also been necessary to form such traces. stylised in the figures given by M'Coy (1851b, p. IB, fig. 11, Occurrence. Upper Ordovician of Barlaes; typical Gala 12). Larger specimens from Barlaes (Fig. 7b) and Stirches Group localities (Thornylee, Buckholm, Ashiesteel); Pro- (Fig. 7c) in greenish mudstone show straight to bent traces, tovirgularia Grits of Penwhapple and Penkill burns; Hawick 2 mm wide and with 5-6 chevrons per cm. Specimens from Rocks (Stirches, Greenhill, various localities in Kirkud- Penwhapple (Nicholson & Etheridge 1880, pi. 23, fig. 3) are brightshire); Riccarton Group (Lockerbie). small forms, 20-30 mm wide, with 15-18 chevrons per cm. Discussion. M'Coy interpreted Protovirgularia as an octo- coral resembling the recent Virgularia, Richter and other 2.7. Ichnogenus Gordia Emmons 1844 German authors thought it was a graptolite, and Hantzschel (1958, p. 84) finally established its trace fossil nature. Gordia marina Emmons 1844 M'Coy gave the locality as "in the slate at Lockerby", and (Fig. 8a,b) the type locality has been identified as probably the old 1844 Gordia marina Emmons, p. 24, pi. 2, fig. 2. railway cuttings there (Peach & Home 1899, p. 213) in the vl848 Palaeochorda minor M'Coy, p. 225. 78 M. J. BENTON vl848 Palaeochorda major M'Coy, p. 225. vl851b Palaeochorda minor M'Coy, pi. 1A, fig. 1, 2. vl851b Palaeochorda major M'Coy, pi. 1A, fig. 3. 1855 Palaeochorda major M'Coy; Harkness, pp. 473-4. 1855 Palaeochorda? teres Harkness, p. 474. ?1855 Trichoides ambiguus Harkness (partim), pp. 474-5. vl978 Nemertites (Palaeochorda) major (M'Coy); Nichol- son, p. 40, pi. 3, fig. 2, 3. vl978 Nemertites (Palaeochorda) minor (M'Coy); Nichol- son, pp. 40-1, pi. 3, fig. 4. Material. GSE M4701a, M4702a from The Whin; RSM unnumb. from Hunterheck; GSM 104243, 104245-6; RSM 1981.30.6-9 from Barlaes; RSM 1981.30.53-5 from Blackcock; RSM 1981.30.85 from Bowden; RSM 1981.30.90 from Binks; RSM 1981.30.93, 98-104 from Stirches. Description. Smooth unbranched burrows that form broad sweeping curves at a single bedding level (Fig. 8a). a Usually preserved as positive and negative epireliefs on siltstone and fine sandstone turbidite soles. Burrow cross- section is circular and the diameter is uniform and varies from 1-2 mm, or 1-4 mm in the case of material from Stirches (Fig. 8b). Some of these specimens and others from the Protovirgularia Grits of Penwhapple appear to form partial networks because of complex crossing. Discussion. Gordia marina was established by Emmons (1844) for a specimen from the Lower Silurian of SE Maine which shows an irregularly looping and crossing burrow of uniform 3 mm width and circular cross-section. The genus Palaeochorda was established by M'Coy (1848, 1851b) for traces from the Ordovician of the Lake District. These are circular burrows that loop irregularly and cross at one sedimentary level, and vary in diameter from 1-5 to 6-0 mm. M'Coy's two species, P. minor and P. major, were distinguished by size alone, but there is a complete spectrum of sizes represented in topotype material and both are best combined and included in Gordia marina. Nicholson (1873, 1978) considered that Nemertites ollivantii Murchison 1839 was a trace of this kind, and he synonymised Gordia and Palaeochorda with Nemertites. However, Murchison's specimen is a basal part of the wall of a Dictyodora and Nichol- son's synonymy is inappropriate. Palaeochorda major, reported by Harkness (1855) from Barlaes, is clearly Gordia, while his new species P. ? teres, which "may be recognised by the gradual tapering of the stems" (Harkness 1855, p, 474) is probably only a variant of the typical Gordia. The obscure Trichoides ambiguus may also include some small Gordia material. The ichnogenus Gordia should be used for non-branching smooth-walled horizontal burrows of uniform width that loop irregularly in broad arcs and frequently cross (Ksiijz- kiewicz 1977). Regularly looping forms are Cosmorhaphe and Helminthopsis. All of these may fall within the bounds of Planolites, but it would be a mistake to include them in that genus since they all display special looping patterns that are recognisable in many different formations. Occurrence. Gordia is common at certain localities in the Upper Ordovician (Barlaes), Gala Group (Blackcock, Hun- ter Hill, Hunterheck, etc.), Protovirgularia Grits (Penwhap- ple), and Hawick Rocks (Bowden, Stirches). Figure 8 (a) Gordia marina, large slab showing typical broad curves and uniform burrow width; Upper Llandovery, Stirches; 2.8. Ichnogenus Megagrapton Ksigzkiewiez 1968 RSM 1981.30.100; x 0-5. (b) Gordia marina, two specimens showing range in width and Megagrapton sp. clarity of preservation; Upper Llandovery, Stirches; (Fig. 8c) RSM 1981.30.98 (left), 99 (right); x 0-5. (c) Megagrapton sp., showing irregular polygons and branching Material. RSM 1981.30.10 from Barlaes; RSM 1976.71.222 burrows; Upper Llandovery, Hunter Hill (Cramalt road sec- from Thornylee; RSM 1981.30.68 from Hunter Hill; RSM tion); RSM 1981.30.68; x 1-0. 1981.30.69, 70 from Hunterheck. r TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 79 Description. Several localities yield irregular network consist of five or six circular burrows, 1-2 mm wide and traces on fine turbidite soles (Fig. 8c). The specimens are 15-25 mm long, branching dichotomously from a common intermediate between Gordia and true regular networks and base. burrow width is 1-4 mm. The most appropriate name is Discussion. Chondrites has been described from several probably Megagrapton (Seilacher 1977). Southern Uplands localities, but I have not seen the speci- Occurrence. Upper Ordovician (Barlaes), Gala Group mens. Harkness (1855, p. 473) described a new species, C. (e.g. Thornylee, Hunter Hill, Craigmichan, Hunterheck, Glenjorrie), Protovirgularia Grits (Penwhapple).

• - "\ 2.9. Ichnogenus Paleodictyon Meneghini 1850 The Llandovery of the Southern Uplands has two forms of Paleodictyon preserved on the soles of turbidites, just as in the Aberystwyth Grits of Wales (Seilacher 1977, p. 330). The size and complexity matches other Silurian examples, showing the "primitive" characters of large size and irregular mesh. The network is interpreted as a long-term "search net", a permanent burrow system designed to trap food material, rather than a simple back-filled feeding trace (Seilacher 1977).

Paleodictyon (Glenodictyon) imperfectum Seilacher 1977 (Fig. 9a) 1969 Paleodictyon, Webby, pp. 85-87, 89, figs 2, 3. v*1977 Paleodictyon (Glenodictyon) imperfectum Seilacher, p. 325, fig. 14d (p. 328). Holotype. University of Edinburgh, Grant Institute of Geology no. 46275, specimen figured by Seilacher (1977) and designated as type. Hawick Rocks, Silurian, Mull Point, near Borgue (not "Bongue"), Kirkudbrightshire-. Figured here, Figure 9a. Description. "Large form with fairly wide meshes of un- equal size and shape; outline of the system angular, probably hexagonal." (Seilacher 1977). The type specimen (Fig. 9a) is unusually well preserved on a grey-green fine sandstone turbidite sole and shows 21 complete polygons in the form of irregular hexagons, as well as numerous partial polygons round the circumference. The polygons are 10-30 mm across and the burrows are 1-0-1-5 mm in diameter and nearly circular in cross-section. The burrows run in straight or slightly curving lines for 10-20 mm before turning at an angle of 10-80°. a Occurrence. Hawick Rocks of Mull Point. Also, Abery- stwyth Grits, Wales (Seilacher 1977, pi. 3).

Paleodictyon (Squamodictyon) petaloideum Seilacher 1977 (Fig. 9b) 1977 Paleodictyon (Squamodictyon) petaloideum Seilacher, p. 324, fig. 13, 14a, b, pi. 3. Material. RSM 1981.30.81 from Penwhapple. Description. "Large form with relatively few and wide meshes of rather irregular shape, arranged like petals around a centre" (Seilacher 1977, p. 324). The Penwhapple specimen (Fig. 9b) has 1-5 mm wide burrows arranged in scale- like polygons, 15-30 mm in diameter, as in Seilacher's material from the Aberystwyth Grits. Occurrence. Base of grey-purple siltstone turbidite in Penkill Group of Penwhapple Glen.

2.10. Ichnogenus Chondrites von Sternberg 1833 Figure 9 Paleodictyon from the Upper Llandovery. (a) P. (Glenodictyon) imperfectum, good network cast on sole of cf. Chondrites sp. fine sand turbidite showing angular polygons; holotype; Mull (Fig. 10a) Point; University of Edinburgh, Grant Institute of Geology no Material. RSM 1981.30.12 from Stobo. 46275; x 0-95. (b) P. (Squamodictyon) petaloideum, tracing of a specimen cast on Description. The specimen from Stobo Slate Quarries fine sand turbidite sole showing curved scale-like polygons- (Fig. 10a) shows three partial branching systems. These Penwhapple; RSM 1981.30.81; x 0-7. 80 M. J. BENTON regularis, from Barlaes, and ascribed other material to C. 2.11. Ichnogenus Planolites Nicholson 1873 informis M'Coy 1851. "Branching bodies" have been men- Planolites sp. tioned from the Hawick Rocks of Binks (Harkness 1856, p. (Fig. 10b, c) 244), and Warren (1964, p. 198) reported a specimen from Material. RSM 1981.30.65, 66 from Thornylee; RSM Adderstonlee, SE of Hawick. 1981.30.82-4 from Eyemouth. Occurrence. Ordovician of Stobo, Barlaes (?). Hawick Description. Infilled subhorizontal non-branching burrows. Rocks of Binks(?), Adderstonlee. Some are preserved as short stretches (5-20 mm) of 1-2 mm

Figure 10 (a) Chondrites sp., two small dichotomously branching systems; Upper Ordovician, Stobo; RSM 1981.30.12; x 0-95. (b) Planolites sp., fine sand turbidite sole with casts of irregular burrows; Upper Llandovery, Eyemouth; RSM 1981.30.82; x 0-75. (c) Planolites sp., very large irregular horizontal burrow and smaller burrows cast on turbidite sole; Upper Llandovery, junction of Penkill and Penwhapple burns; tracing from a field photograph; x 0-15. (d) Skolithos sp., bedding plane view of vertical burrows in medium-grained laminated sandstone; Upper Llandovery, Thornylee; RSM 1981.30.59; x 0-45. TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 81 diameter burrow in grey-green mudstone from Thornylee. In because identical forms may be present in Ashgill and other cases, fine sand and siltstone turbidite soles preserve Llandovery sediments, and it is necessary to seek environmen- numerous confused casts of segments of 1-2 mm wide bur- tal explanations. rows (e.g. Fig. 10b). Several bedding planes exposed at the Sedimentary logs with the occurrence of trace fossils are mouth of Penkill burn show casts of very large irregular given in Figure 11. The Stirches section consists of thick beds burrows (5-20 mm wide) on turbidite soles (Fig. 10c). In all of massive fine- to medium-grained sandstone greywackes at cases, the burrows are much more irregular than Gordia. top and bottom, separated by scour surfaces and rare mud- Occurrence. Within and on soles of mudstone, siltstone stones. The central portion is a sequence of laminated red and fine sand turbidites at Thornylee, Eyemouth, Hunter and grey-green shales and thin laminated siltstone interbeds. Hill, Craigmichan, Penwhapple. Trace fossils occur in the shales (Helminthoida, Caridolites),

2.12. Ichnogenus Skolithos Haldemann 1840

Skolithos sp. silt sand silt sand (Fig. lOd) clay^ \ in c clay f m c Material. RSM 1981.30.11 from Stobo; RSM 1981.30.59 from Thornylee; RSM 1981.30.89 from Binks; RSM 1981.30.91 from Stirches; RSM 1981.30.108 from Yadd Linn. Description. Fine grey-green or blue-grey laminated turbidite sandstones from many localities preserve short vertical burrows. A specimen from Thornylee (Fig. lOd) shows about 50 circular impressions in a bedding plane area of 20 cm2. The impressions are 4-6 mm in diameter, filled with brown material, and show no signs of pairing. Their top part is slightly depressed and they taper through the 3 cm thick slab, appearing as 2-4 mm circular bumps on the lower side. In other examples, the burrows are 1-3 mm in diameter, but they are usually at least 15 mm deep. Discussion. Harkness (1856, p. 242) described "pitted hollow markings on the surfaces of the strata . . . (that) extend through the thickness of the stratum" from Binks Quarry. He ascribed them to the action of currents forming hollows at obstacles, but the description indicates Skolithos. Rust (1965b, pp. 238-9, pi. 1, fig. 3) described similar Skolithos from Wigtownshire. Similar preservational aspects may be seen in Upper Ordovician material of S. delicatulus figured by Osgood (1970, pp. 327-8, pi. 62, figs 7, 8). Occurrence. Laminated siltstones and fine-grained sandstones of all ages at many localities such as Stobo, Thor- nylee, Stirches, Binks, Palmallet Point, Yadd Linn. 0.5-!——' 2.13. Ichnogenus Protichnites Owen 1852

Protichnites scoticus Salter 1856 1856 Protichnites scoticus Salter, in Harkness, pp. 243^-, fig. 2. 1859 Protichnites scoticus Salter; Murchison, p. 168, fig. 23. 1866 Tracks of Crustacea, Salter, p. 71, fig. 19. STIRCHES CRAMALT THORNYLEE 1871 Protichnites scoticus Salter; Lapworth & Wilson, p. 458. KEY The type specimen of P. scoticus from Binks has not been found. The illustration shows a paired trail of bifid imprints with an intermittent median drag trail. The total width of the laminated shale Caridolites trail is 15-25 mm and it appears to match the characters of Dictyodora the ichnogenus Protichnites. The specimen from Ellemford laminated siltstone Gordia (Salter 1866) is rather different, and is probably an example of Neonereites biserialis very like that figured here (Fig. 5d) massive greywacke Helminthoida from Greenhill. Meqagrapton shale clasts / " Neonereites 3. Discussion scour surface Planolites V Skolithos 3.1. Environmental interpretation The foregoing review of the trace fossils of the Ordovician Figure 11 Sedimentary logs and trace fossil occurrences in sections at Stirches Quarry [NT 498 168], a low level in the Cramalt road and Silurian of the Southern Uplands has shown that each section, Hunter Hill [NT 200 229] and in the middle of the Thorn- locality yields different ichnogenera, and there appear to be ylee section, above the scree [NT 4200 3635]; note the different associations. These cannot be ascribed to age differences scale for the Thornylee log. 82 M. J. BENTON on the siltstone soles (Gordia), and in the siltstones (Sko- regimes, both in the mudstones and the thin greywackes. lithos). No trace fossils were found in the thick greywackes. Higher energy sequences (e.g. Cramalt, parts of Stirches The Cramalt section consists of thick massive fine- to section) only have rare trace fossils. coarse-grained graded greywackes, separated by scoured and In the Southern Uplands, the Nereites subfacies may be loaded surfaces, and often containing large shale clasts. In further divided (Fig. 12). In some cases, Dictyodora scotica the middle part of the section shown here, interbedded is heavily dominant and Gordia is absent; in others, the two laminated siltstones and fine-grained sandstones occur. forms are equally abundant, and yet others have only D. Trace fossils are found abundantly cast on the bases of a few tenuis and Caridolites with no D. scotica or Gordia. The sandstones (Planolites, Megagrapton). environmental controls on these assemblages are not certain The Thornylee section is a simple sequence of laminated but oxygen content of the sediment may be involved since siltstone and purple shale interbeds. The bases of the silt- D. scotica is nearly always associated with primary red or stones may be scoured, and their internal structures (scour purple mudstone, and D. tenuis with grey-green mudstone. and fill, parallel and cross lamination, grading) point to A few localities only yield specimens of Nereites or Protovir- deposition by weak turbidity currents (Walton 1956; Trewin gularia in mudstone, and these must be separated as further 1979). Trace fossils occur within the siltstones (Skolithos) "assemblages" until further information is available. and abundantly throughout the shales (Dictyodora, Carido- The red or purple colour of some Gala Group and Hawick lites, Neonereites). Rocks mudstones has been explained in terms of rapid The most important control on trace fossils here, and in deposition of oxidised source material during periods of many other flysch sequences, is their relationship to turbidity transgression (Ziegler & McKerrow 1975). These authors flow. Seilacher (1974) divided the Nereites Facies into a pointed out that "organic productivity can be inferred to be Nereites subfacies (thick accumulations of mudstone and low in the areas of red bed accumulation", but the abundant siltstone with weak turbidity currents) and a Paleodictyon trace fossils in places suggests considerable biological subfacies (fine to medium turbidite sands with casts of trace activity. fossils on soles). In the first case, traces are preserved largely The Paleodictyon subfacies may be divided into pre- in their original form, while in the latter, the superincum- depositional and post-depositional associations (Fig. 12). bent unconsolidated mud was usually removed by a turbidity The pre-depositional burrows are those that were exhumed current, and exposed burrow systems were cast in sand. and cast by a turbidity current, and the post-depositional Thus, we may class all the meandering trace fossils found in burrows are those made in the turbidite silt or sand after it the shales (Dictyodora, Helminthoida, Neonereites, Carido- settled (Seilacher 1962). lites) as belonging to the Nereites subfacies, and those cast on The main components of these assemblages are given the bases of siltstones and sandstones (Gordia, Megagrap- below, and they are summarised in Figure 13. The localities ton), and those within these coarser beds (Skolithos) as are divided up according to this outline in Figure 1 and belonging to the Paleodictyon subfacies. It is clear that trace Table 1, and some localities show more than one assemblage fossils are most common in the low energy turbidity current in different facies.

III Paleodictyon subfacies (post-turbiditeX

I Nereites subfacies

II Paleodictyon subfacies (pre-turbidite)

Figure 12 Diagrammatic representation of trace fossils on the Lower Palaeozoic ocean-floor of the Southern Uplands; a vertical scale is not implied and it would be most unlikely to find all the subfacies in such close association. I Nereites subfacies (with turbidity currents) 1 Dictyodora scotica assemblage; 2 Dictyodora scotica and Gordia assemblage; 3 Dictyodora tenuis and Caridolites assemblage; 4 Nereites pugnus assemblage; 5 Protovirgularia assemblage. II Paleodictyon subfacies, pre-turbidite (traces exhumed and cast by turbidity current) 6 Gordia and Paleodictyon assemblage. Ill Paleodictyon subfacies, post-turbidite (traces in turbidite) 7 Skolithos assemblage. Trace fossils a Dictyodora scotica, b D. tenuis, c Caridolites, d Neonereites, e Protovirgularia, f Nereites, g Gordia, h Paleodictyon, i Skolithos. Common preservational aspects of the trace fossils and typical sedimentary structures (fine parallel lamination, cross-lamination, scour surfaces) are shown. TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 83 A. Nereites subfacies Paleodictyon assemblage. In many localities it occurs on its 1. Dictyodora scotica assemblage (localities 3-9, 12-15, 17- own, both within laminated shales and cast on siltstone 24, 32, 35 (?), 36 (?), 46 (?)). The readily recognisable D. turbidite soles; for these cases it merits a separate "assemb- scotica occurs in great abundance (80-100% of specimens) at lage" designation. all localities and is often the only trace fossil found. It is recognised as regularly looping basal burrows or wall sec- B. Paleodictyon subfacies tions on bedding planes and loose slabs of red or purple 6. Gordia and Paleodictyon assemblage (pre-turbidite) mudstones, or as "keyhole" shapes on vertical sections. The (localities 1-3, 26-30, 32-34, 37-39, 43, 47). Gordia is the shale slabs often break vertically along walls. Associated commonest trace fossil (60-80%) preserved as sole casts on trace fossils include Caridolites (5%) and rare D. tenuis, grey-green siltstone to medium-grained sand turbidites. small Nereites, Neonereites, and Planolites. Paleodictyon, Megagrapton, irregular Planolites, and Most localities are within the typical Gala Group beds in Chondrites are rarer elements. the area of Lauder, Galashiels, and Innerleithen, but other 7. "Skolithos assemblage" (post-turbidite) (localities 1, 23, localities range from Siccar Point on the E coast to Galloway 37, 39, 45, 47). Skolithos occurs within siltstone and fine t o on the W coast. The Crossopodia Shales of the Penkill medium grained sand turbidites. Group of Penwhapple Glen, Girvan, are very similar in terms of trace fossils, age, and lithology. The Ordovician of 3.2. Comparison with other areas Barlaes contains typical D. scotica assemblages, but they are The Lower Palaeozoic rocks of the Longford-Down massif found only rarely in the Hawick Rocks. of Northern Ireland, a continuation of the Southern Uplands 2. "Dictyodora scotica and Gordia assemblage" (locality accretionary prism, have yielded trace fossils in Llandovery 11). This is probably a subsidiary of the first assemblage; D. mudstones (Doughty 1980). The forms present {Dictyodora scotica is still the most abundant trace fossil (60%), but scotica dominant, Neonereites) indicate the typical D. scotica Gordia, absent in the D. scotica assemblage, is common also assemblage. Another specimen (Doughty 1980, pi. 6, fig. 1 ) , (30%). Caridolites also occurs. The specimens of Gordia are described as Phycosiphon, could be a D. tenuis basal bur- very like those of the Paleodictyon subfacies and this is row, but it does seem rather different from Southern Up- evidently the same trace fossil preserved in shale without lands forms. having been cast on a turbidite sole, the mudstones are red The following are other Lower Palaeozoic flysch sequ- or purple, often showing reduction spots and discontinuous ences that have yielded ichnofaunas similar to those of the parallel lamination. The locality is well within the area of Southern Uplands. distribution of the typical Gala Group. 1. Aroostock-Matapedia Carbonate Belt (Ordovician), New 3. Dictyodora tenuis and Caridolites assemblage (localities Brunswick: Alcyonidiopsis, Buthotrephis, Chondrites, 10,16, 25, 31). The small trace fossils D. tenuis and Carido- Fucosopsis, Gyrochorte, Helminthopsis, Planolites, Sca- lites are the only forms present, and in the proportion of larituba, Taenidium (Pickerill 1980). . 2:1, and they occur on bedding planes of laminated grey- 2. Barrancos, Portugal (Upper Ordovician): Dictyodora, green shales. These forms also occur elsewhere in the Paleodictyon, Gordia, Nereites, cf. Diplichnites (Delgado D. scotica assemblage, but rarely. 1910). , 4. Nereites pugnus assemblage (localities 29, 37, 47). Large 3. Grafenthaler Serie (Upper Ordovician), Wiinschendorf, forms of Nereites (N. pugnus) occur in grey-green laminated E Thuringia: Dictyodora, Diplocraterion, Planolites shales. Smaller Nereites (N. macleayi, N. cambrensis, N. (Hundt 1912; Benton 1982). jacksoni) are typical of the D. scotica assemblage, but N. 4. Aberystwyth Grits, Devil's Bridge Formation, etc. (Up- pugnus is apparently never associated with Dictyodora. Hel- per Llandovery), Central Wales: Nereites, Paleodictyon, minthoida occurs in similar lithologies at Stirches and Hun- Dictyodora, Chondrites (Crimes 1970, pp. 109-10). terheck, and it is included here as a possible associate. 5. Waterville Formation (Lower-Middle (?) Silurian), 5. "Protovirgularia assemblage" (localities 32, 36, 40-42, Maine: Nereites, Gordia (Emmons 1844). 44, 48). Protovirgularia has been found associated with D. 6. Quidong, New South Wales (? Upper Llandovery): scotica and as an element of the pre-turbidite Gordia and Paleodictyon, ? Gordia (Webby 1969).

O rare *<5% * * 5-80% ^**80-100%

TRACE FOSSL ASSEMBLAGES b d >0 / m m 1/ A Nereites subfacies

1 Dictyodora scotica *** o o o o o 2 D. scotica/Gordia * * o * *

3 D. tenuis/Caridolites •** ** 4 Nereites pugnus *** 5 Protovirgularia *** B Paleodictyon subfacies

6 Gordia/Paleodictyon (pre-) *** * * oo 7 Skolithos (post-) ***

Figure 13 Trace fossil assemblages and proportions of the main constituents in the Lower Palaeozoic of the Southern Uplands; a Dictyodora scotica, b D. tenuis, c Caridolites, d Neonereites, e Nereites (small), f Nereites (large), g Protovirgularia, h Gordia, i Megagrapton, j Paleodictyon, k Chondrites, 1 Planolites, m Skolithos. 84 M. J. BENTON 7. Ardoises a Nereites (Lower Devonian), Bourg d'Oueil, NW of Langshaw and 5 km NNE of Galashiels; small Pyrenees, France: Nereites, Dictyodora (Barrois 1884). quarry with good exposure, now a small bore gun range. 8. Nereitenschiefer (Middle Devonian), Thuringia: Nereites, 12. Avenel Quarries [NT 5250 2679, NT 5268 3684], S side Neonereites, Protovirgularia, Gordia, Chondrites, of Westa Hill, just below Avenel Plantation and the Lophoctenium (Pfeiffer 1968; Benton 1982). "Faerie's Bowling Green", 1-3 km NE of Easter Lang- lee Farm and 3 km E of Galashiels (Peach & Home Most of these ichnofaunas are dominated by Nereites 1899, p. 203—"Allan Water"). which is relatively rare in the Southern Uplands. The only 13. Westerhill Quarry [NT 5073 3619], old quarry on N side localities with relatively frequent Dictyodora scotica-Xike of Wester Hill, 400 m S of Langlee Mains Farm, 1 km E forms are Barrancos and Wiinschendorf. The overwhelming of Galashiels. dominance of Nereites in some places, and of Dictyodora in 14. Buckholm Mill Quarry [NT 4820 3737], E side of A7 others must be significant. Nearly identical forms of these trunk road, opposite Old Buckholm Mill, on the NW traces may occur in Ordovician, Silurian and Devonian boundary of Galashiels (Peach & Home 1899, p. 203); flysch, so that the deep-sea assemblage present probably the quarry is largely filled in and Peach & Home's depends on environmental factors rather than age. quarry (Buckholmside), 500 m to the N, is also filled. 15. Ladhope Burn [NT 4965 3777], E side of Buckholm Hill, 1-5 km NE of the centre of Galashiels; streambed 4. Localities section accessible from the track across Ladhope Moor Ordovician and Silurian trace fossil localities of the Southern that starts at Galashiels golf course. Uplands are arranged below stratigraphically and geographi- 16. The Whin [NT 4690 3895], old railway cutting 200 m W cally (cf. Fig. 1; Table 1). of The Whin house, 2-5 km NW of Galashiels.

Late Ordovician (Caradoc-Ashgill) Gala (Queensberry) Group, Galashiels-Innerleithen area 1. Stobo Slate Quarries [NT 158 365], on S face of Quarry 17. Caddonfoot Quarry [NT 4490 3519], 220 m N of Cad- Hill, 4 km E of Broughton, Lowther Beds (Leggett donfoot, on E side of B710 road, 4-5 km WSW of 1980). Galashiels (Peach & Home 1899, pp. 203^1— "Cadonfoot"; their quarry "a few yards to the south- 2. Coulter Craigs [NT 0282 3228], 1 km S of Coulter on east of the schoolhouse" is now filled. minor road. 3. Barlaes Quarry [NX 6228 8565], on W side of Barlaes 18. Caddonlee Quarry [NT 4487 3552], quarry on E side of Hill, 400 m E of Barlaes Cottage, 4-5 km N of St John's B710 road just S of the house Caddonlinn, 4-5 km W of Town of Dairy (Harkness 1855). Galashiels (Peach & Home 1899, p. 204—"Cad- onlee"). Gala (Queensberry) Group, eastern inliers (Berwickshire) 19. Meigle Quarry [NT 4563 3691], roadside quarry on A72, 4. Old Cambus Quarry [NT 8065 7041], large disused quar- 500 m NE of Meigle farm, 1 km NE of Clovenfords, ry 500 m NE of Old Cambus West Mains farmhouse, 4 km W of Galashiels (Peach & Home 1899, p. 204); and 500 m SW of Siccar Point, 2-5 km SE of Cockburn- quarry now filled in. spath (Salter 1866, p. 70; Peach & Home 1899, p. 209). 20. Newhall Farm [NT 4230 3765], exposures on the Cad- Specimens common in a small excavation on the W side don Water 200 m SW of Newhall Farm, 3 km WNW of of the main quarry. Clovenfords, 7 km W of Galashiels (Peach & Home 1899, p. 205). 5. Ellemford [NT 732 596], old quarry on the B6355 road, 600 m SE of the bridge over the Whiteadder Water. 21. Ferniehirst [NT 445 415], exposures in banks of burn S Salter (1866, p. 71) described some "tracks of Crus- of Old Ferniehirst, 4 km NW of Clovenfords. tacea" which are possibly Neonereites. 22. Caddonhead Farm [NT 4026 4115], old quarry behind 6. Heron's Hole, River Dye [NT 6814 5719], 1 km W of the farm, 7 km WNW of Clovenfords (Peach & Home Longformacus, 10 km WNW of Duns; limited exposures 1899, p. 205). on steep banks at sharp bend in river; access from 23. Thomylee Quarry [NT 4200 3635], a small quarry and behind Rathburne Hotel on S side of the river. scree beside a dismantled railway above a lay-by on the 7. Wedderlie Farm Quarry [NT 6440 5165], on roadside A707 road, 4 km WNW of Caddonfoot; the railway 250 m S of Wedderlie Farm, 2 km E of Westruther; cutting exposes a 300 m section of interbedded mud- exposure limited. stone and greywacke (Nicol 1850, p. 56; Lapworth 1870; 8. Bruntaburn (or Boondreighburn) [NT 5922 5192, Peach & Home 1899, pp. 204-5; Benton & Trewin NT 5913 5208], two small exposures on the left side of 1980). the broad floodplain of the burn, 1-5 km NNW of Old 24. Holylee Farm [NT 3925 3754], just N of the A707 road, Bruntaburn Farm, 5 km WNW of Westruther (Peach & 3 km E of Walkerbum. The old quarry at Home 1899, pp. 206-7). [NT 3930 3767], marked on Peach & Home's 6-inch maps (in Institute of Geological Sciences, Edinburgh), is 9. Blythe Water Quarry [NT 5742 4981], 1-2 km W of filled, but trace fossils may be found in loose blocks Blythe Farm, 5 km ENE of Lauder; old quarry with nearby. good exposure and large scree (Peach & Home 1899, p. 207—"Blythe Burn"). 25. Grieston Quarry [NT 314 362], 300 m W of Howford 10. Earnscleugh Burn, Bermuda Shepherd's House farmhouse, 2 km WSW of Innerleithen; a large quarry [NT 5582 5395], on stream side between Hogs Law and with good exposure; type locality of the griestoniensis Edgarhope Law, 7-5 km NE of Lauder (Peach & Home Zone (Nicol 1848, p. 204; 1850, pp. 53-5; Lapworth 1899, pp. 196-7). 1870; Peach & Home 1899, p. 206; Toghill & Strachan 1970; Trewin 1979; Benton & Trewin 1980). Gala (Queensberry) Group, Galashiels-Lauder area Gala (Queensberry) Group, Moffat area 11. Blackcock Plantation Quarry [NT 5032 4078], roadside 26. Hunter Hill, Cramalt road section [NT 200 229] above quarry on the road from Langshaw to Lauder, 1-5 km Meggett Reservoir, 5 km W of Cappercleuch. TRACE FOSSILS FROM OCEAN-FLOOR SEDIMENTS 85 27. Dobs Linn [NT 195 158], 500 m N of A708 road, 15 km as "Bongue"). NE of Moffat (Lapworth 1878, pp. 247-60; Peach & 44. Garlieston Bay [NX 490 465], N side of bay on shore, Home 1899, pp. 92-100); exact locality uncertain, but 1 km E of Garlieston (Peach & Home 1899, p. 216— probably waterfall section on Linn branch of the stream " G a r l i e s t o w n " ) . (sedgwicki Zone). 45. Palmallet Point [NX 484 422], on shore 500 m E of 28. Craigmichan Scaurs [NT 159 062], large exposure at Palmallet farmhouse, 4 km SSE of Garlieston; vertical head of Selcoth Burn, 7 km E of Moffat; accessible burrows (Skolithosj in laminated siltstone (Rust 1965b, along a footpath on the SW side of the burn, starting at pp. 238-9, pi. 1, fig. 3). Selcoth (Lapworth 1878, pp. 260-5; Peach & Home 1899, pp. 100-7; Fyfe & Weir 1976). Riccarton Group 29. Hunterheck Hill [NT 110 050], screes on SE face of the 46. Stobs Castle Quarry [NT 507 085], 300 m SE of Stobs hill just above the A708 road, 2 km E of Moffat (Hop- Castle, 6 km S of Hawick (Warren 1964, p. 200); the kinson 1870; Lapworth 1870, p. 55; Peach & Home locality "immediately below Stobs Castle" that yielded 1899, p. 210). abundant tracks (Peach & Home 1899, p. 559) was not found. Gala (Queensberry) Group, western area 47. Yadd Linn [NT 5298 0500], exposure on bend in B6399 30. Glenjorrie Quarry [NX 208 577], extensive quarry open- road, 1 km SSE of Shankend, 10 km SSE of Hawick. ings just N of A75 road, 1 km E of Glenluce (Kilfillan 48. Lockerbie [NY 137 819, 138 822], railway sections, the Formation of Gordon 1962). former filled in, the latter largely overgrown; ? type 31. Garrochtrie [NX 113 387], 2 km NW of Kirkmaiden, locality of Protovirgularia dichotoma M'Coy (1850, p. Galloway. 272-3—"in the slate at Lockerby"); Peach and Home (1899, p. 213) reported Protovirgularia from "a railway Penkill Group, Protovirgularia Grits, Girvan area cutting near Lockerbie". 32. Penwhapple Glen [NX 229 984, NX 230 983] and Penk- ill Burn [NX 232 985], stream gorge sections, 1 km S of Old Dailly, 4-5 km E of Girvan (Lapworth 1882, p. 652; 5. Acknowledgements Nicholson & Etheridge 1880, pp. 304-18; Peach & I am deeply indebted to P. J. Brand, D. N. Lewis, R. B. Home 1899, pp. 520, 545; Cocks & Toghill 1973, pp. Rickards, W. D. I. Rolfe, W. A. Rushton, I. Strachan, N. 227-8). H. Trewin and R. Wilson for loan of specimens and study facilities, to P. Aspen, D. Casey, E. N. K. Clarkson, M. Hawick rocks, eastern outcrops Monro, G. A. Peace, N. H. Trewin and J. A. Weir for 33. Eyemouth coast [NT 954 644], 1 km E of the town; locality information and assistance in the field, to T. P. correlation of these beds with the Hawick Rocks is Crimes and N. H. Trewin for critical comments and to P. J. uncertain. Brand, M. Dorling, D. N. Lewis and C. D. Waterston for 34. Bowden Burn [NT 5542 3024], small quarry on side of provision of illustrations. stream, 200 m S of Bowden, 2-8 km WSW of Newtown St Boswells. 35. Selkirk Common quarries [NT 479 279, NT 478 276, etc.], 1 km SE of Selkirk; Peach and Home (1899, p. 6. References 208) report "Crossopodia, Myrianites and other tracks" Barrois, Ch. 1884. Sur les ardoises a Nereites de Bourg d'Oueil. from this area, but I found no specimens; many of the ANN SOC GEOL NORD 11, 219-26. old quarries are now filled in. Benton, M. J. 1982. Dictyodora and associated trace fossils from the Palaeozoic of Thuringia. LETHAIA 15, 115-32. 36. Greenhill [NT 4802 2495], old quarry on the roadside, Benton, M. J. & Trewin, N. H. 1978. Discussion and comments on just off the A7 trunk road, 300 m NW of New Greenhill Nicholson's 1872 manuscript 'Contributions to the study of the farmhouse, 2-5 km S of Selkirk (Peach & Home 1899, Errant Annelides of the older Palaeozoic rocks'. PUBL DEP p. 208). GEOL MINERAL UNIV ABERDEEN 1, 1-16. 37. Stirches Quarry [NT 498 168], an extensive quarry run- Benton, M. J. & Trewin, N. H. 1980. Dictyodora from the Silurian of Peeblesshire, Scotland. PALAEONTOLOGY 23, 501-13. ning NE from the road, 600 m N of Stirches farmhouse, Bulman, O. M. B. 1955. Graptolithina. In Moore, R. C. (ed.) 2-5 km N of Hawick (Peach & Home 1899, p. 208). Treatise on Invertebrate Paleontology, Vl-101. New York, 38. Adderstonlee [NT 529 114], locality near farm, 4 km SE Lawrence: Geological Society of America, University of of Hawick (Warren 1964, p. 198). Kansas. Bulman, O. M. B. 1970. Graptolithina. In Teichert, C. (ed.) 39. Binks [NT 4026 0407], old quarry on A7 trunk road Treatise on Invertebrate Paleontology, Vl-163. New York, opposite picnic site, 800 m SW of Binks farmhouse, Lawrence: Geological Society of America, University of 1-5 km S of Teviothead (Harkness 1856). Kansas. Clarkson, C. M., Craig, G. Y. & Walton, E. K. 1975. The Silurian Hawick Rocks, western outcrops rocks bordering Kirkudbright Bay, South Scotland. TRANS R SOC EDINBURGH 69, 313-25. 40. Halketleaths [NX 799 634], railway cutting (old Dum- Claus, H. 1965. Eine merkwiirdige Lebensspur (Protovirgularia ? fries-Kirkudbright line), near Halketleaths Mill, 3 km E sp.) aus dem Oberen Muschelkalk NW-Thuringens. SENC- of Castle Douglas (Peach & Home 1899, p. 215). KENB LETHAIA 46, 187-91. 41. Castle Douglas Station [NX 769 628] (Peach & Home Cocks, L. R. M. & Toghill, P. 1973. The biostratigraphy of the Silurian rocks of the Girvan district, Scotland. J GEOL SOC 1899, p. 215). LONDON 129, 209-43. 42. Torrs Point [NX 672 453], on shore 300 m N of Torrs Craig, G. Y. & Walton, E. K. 1962. Sedimentary structures and Point (Peach & Home 1899, p. 215), 1 km SW of Torrs palaeocurrent directions from the Silurian rocks of Kirkud- farm. brightshire. TRANS EDINBURGH GEOL SOC 19, 100-19. 43. Mull Point [NX 636 445], on shore 1-5 km WSW of Crimes, T. P. 1970. The significance of trace fossils in sedimentology, stratigraphy and palaeoecology with examples from Lower Brighouse, 4 km ESE of Borgue; type locality of Palaeozoic strata. In Crimes, T. P. & Harper, J. C. (eds) Trace Paleodictyon imperfectum Seilacher 1977 (locality given Fossils, 101-26. GEOL J SPEC ISSUE 3. M. J. BENTON Delgado, J. F. N. 1910. Terrains paleozoiques du Portugal. Etude NAT HIST (2) 6, 270-90. sur les fossiles des schistes a nereites de San Domingos et des M'Coy, F. 1851a. On some new Protozoic Annulata. ANN MAG schistes a riereite et a graptolites de Barrancos. COM SERV NAT HIST (2) 7, 394-6. GEOL PORTUGAL 56, 1-68. 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Seventh report Murchison, R. I. & Morris, J. 1855. On the Palaeozoic and their of the committee on the fossil Phyllopoda of the Palaeozoic associated rocks of the Thiiringerwalde and the Harz. Q J rocks. REP BR ASSOC ADV SCI 1889 (1890), 63-8. GEOL SOC LONDON 11, 409-50. Fyfe, T. B. and Weir, J. A. 1976. The Ettrick Valley Thrust and the Nicholson, H. A. 1873, Contributions to the study of the errant upper limit of the Moffat Shales in Craigmichan Scaurs (Dum- annelides of the older Palaeozoic rocks. PROC R SOC LON- fries & Galloway Region: Annandale & Eskdale District). DON 21, 288-90. SCOTT J GEOL 12, 93-102. Nicholson, H. A. 1978. Contributions to the study of the errant Gordon, A. J. 1962. The Lower Palaeozoic rocks around Glenluce, annelides of the older Palaeozoic rocks. PUBL DEP GEOL Wigtownshire. Unpublished PhD Thesis, Edinburgh Uni- MINERAL UNIV ABERDEEN 1, 17-47. versity. Nicholson, H. A. & Etheridge, R. 1878-1881. A Monograph of the Giimbel, C. W. 1879. 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MICHAEL J. BENTON, Department of Geology, The University, Newcastle upon Tyne, NE1 7RU, : England. (Present address: University Museum, Parks Road, Oxford, OX1 3PW, England.) MS received 28 May 1981. Accepted for publication 13 July 1982.