Ballagan Formation

The Ballagan Formation is a

Willie's Hole, near Chirnside, is another site known for its high quality of preservation. It was initially recognized for its crustacean fossils, forming "shrimp beds" akin to those observed throughout the later Scottish Carboniferous.^[19] Willie's Hole has continued to produce well-preserved fossils of arthropods, fish, and partial tetrapod skeletons.^{[5][20][21][22]}

By far the largest exposures of the Ballagan Formation occur along the coastal end cliffs of Burnmouth.^[5][23][24] Tetrapod, fish, and arthropod fragments are common in several layers at Burnmouth, not just in fine-grained overbank deposits^{[20][22][25][26]} but also coarse river channel conglomerates, an unusual mode of preservation.^[27][28]

Tetrapod fossils have been found in the vicinity of Tantallon Castle.^[5][29] Additional Midland Valley sites include Crumble Edge (along Whiteadder Water),^[30] Coldstream,^[5][31] Cockburnspath,^[32][5] Cove (in Berwickshire),^[31] and Whitrope Burn (near Hawick).^[33] A few locales in nearby Northumberland, England encompass fossil-bearing outcrops of the Ballagan Formation, such as Berwick-upon-Tweed^[34][35] Barrow Scar (near Alwinton),^[31] and a borehole core at Norham.^[23][24]

Some sites are also found along the west coast of Scotland. Auchenreoch Glen, near Dumbarton, was the collection site for the nearly complete type fossil of Pederpes finneyae, which was the oldest named tetrapod of the Carboniferous upon its discovery.^[36] Diverse assemblages of fish teeth and other microfossils have been found at Ayrshire^[37][31] and at Hawk's Nib and Mill Hole, on the Isle of Bute.^[38]

The Ballagan Formation preserves a plethora of tetrapod, fish, and invertebrate fossils, reconstructing one of the most diverse continental ecosystems known from the Tournaisian stage. A variety of plant megafossils and spores are known from the Ballagan Formation.^{[11][39][37][40][41]}

• Aytonerpeton microps^[20][26]
• Diploradus austiumensis^[20][26]
• Koilops herma^[20]
• Mesanerpeton woodi^[21]
• Ossirarus kierani^[20]
• Pederpes finneyae (Whatcheeriidae)^[36][42]
• Perittodus apsconditus^[20]
• Tantallognathus woodi^[29]
• UMZC 2011.7.2: A small unnamed five-fingered tetrapod similar to Gephyrostegus and Silvanerpeton^[5]
• SPW 4165 ("Ribbo"): A large unnamed tetrapod with robust ribs and limbs^[5]
• Crassigyrinus-like bone fragments^[5][28][27]
• An
  Eogyrinus-like tetrapod scute^[16]
• Indeterminate Tetrapoda and Whatcheeriidae fragments.[5]^[27][26]

• Acanthodidae),^[15][43] Gyracanthus sp. (Gyracanthidae),^{[15][43][5][26][27]} and rare indeterminate Climatiiformes.^{[38] [35]}
• Actinisitia (coelacanths): cf. Rhabdoderma^[43]
• Cosmoptychiidae),^[9] Phanerosteon ovensi (Carbovelidae),^[15][9][5] Strepheoschema fouldenensis (Strepheoschemidae),^[15][9] Styracopterus fulcratus (Styracopteridae)^[9]
• Chondrenchelyidae),^[33] Helodus ?simplex (Helodontiformes),^[33] Onychoselache (shark fin spines),^[27] Platyxystrodus sps. (Chondrenchelyidae),^[33] Protacrodus sp. (Protacrodontidae),^[33] Whitropus longicalcus (Cochliodontiformes)^[33]
• Dipnoans (lungfish): Ballagadus caustrimi,^[31] Ballagadus rossi,^[31][26] Coccovedus cellatus,^[31] Ctenodus roberti,^[31][26] Ctenodus whitropei,^[31] Ctenodus williei,^[31] Limanichthys fraseri,^[25] Occludus romeri,^[31] Uronemus splendens,^[26] Xylognathus macrustenus^[31][26]
• Megalichthyidae: ?Megalichthys sp.^[38]
• Rhizodonts: cf. Archichthys portlocki,^[15][38][35] Strepsodus? anculomanensis,^[10] cf. Strepsodus sauroides^[38]
• Indeterminate Actinopterygii.^{[9][5][38][27][26][35]}
• Indeterminate
  Xenacanthiformes,^[35] Hybodontiformes,^[33][35] ctenacanths,^[33][35] and Menaspiformes.^[26]
• Indeterminate fragments of lungfish and rhizodonts,[10]^{[5][38][26][35]} some estimated up to 3 meters or 10 feet in length^[27]

• Pseudotealliocaris etheridgei,^[18][19] Tealliocaris^[19]
• Millipedes: Woodesmus sheari^[22] and at least five other millipede taxa, including members of Archipolypoda, Juliformia, and Euphoberiidae^[5][22]
• Rolfeia fouldenensis (Paleolimulidae)^[13]
• Scorpions:^[19][5] Gigantoscorpio cf. willsi (Gigantoscorpionidae),^[13] Trachyscorpio squarrosus (Eoscorpiidae)^[13]
• "Cyrtoctenus" (Hibbertopterus) peachi (Hibbertopteridae)^[44][13]
• Polyurida aenigmatica, an enigmatic worm-like animal initially mistaken for a myriapod^[14]
• "Spirorbiform" microconchids,^[45][35] initially mistaken for Spirorbis polychaete worm tubes^[6][16][19]
• Ostracods^{[6][46][19][37][40][47][48][35]}
• Bivalves:^[19] Modiolus latus (Mytilidae),^[6][16][35] Naiadites,^[35] Schizodus^[35]
• Gastropods^[15][35]
• Brachiopods^[35]

• List of fossiliferous stratigraphic units in Scotland