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66-613: The Ballagan Formation is a geologic formation in Scotland and England . It preserves fossils dating back to the early part of the Carboniferous period ( Tournaisian – early Visean ). Its name comes from the " Ballagan Beds " of Ballagan Glen, near Strathblane , which has a good example of this geological formation. The Ballagan Formation was historically known as the Cementstone Group , but more recently it has been placed as

132-403: A faunal assemblage , rather than an individual species — this allows greater precision as the time span in which all of the species in the assemblage existed together is narrower than the time spans of any of the members. Further, if only one species is present in a sample, it can mean either that (1) the strata were formed in the known fossil range of that organism; or (2) that the fossil range of

198-419: A basis for defining geologic periods , and then for faunal stages and zones. Species of microfossils such as acritarchs , chitinozoans , conodonts , dinoflagellate cysts, ostracods , pollen , spores and foraminiferans are amongst the many species have been identified as index fossils that are widely used in biostratigraphy . Different fossils work well for sediments of different ages. To work well,

264-479: A boom around 1,000  million years ago , increasing in abundance, diversity, size, complexity of shape, and especially size and number of spines. Their increasingly spiny forms in the last 1 billion years may indicate an increased need for defence against predation. Acritarchs may include the remains of a wide range of quite different kinds of organisms—ranging from the egg cases of small metazoans to resting cysts of many kinds of chlorophyta (green algae). It

330-647: A calcareous or chitinous bivalve-like shell. There are about 70,000 known species, 13,000 of which are extant . Ostracods are typically about 1 mm (0.039 in) in size, though they can range from 0.2 to 30 mm (0.008 to 1.181 in), with some species such as Gigantocypris being too large to be regarded as microfossils. Conodonts ( cone tooth in Greek) are tiny, extinct jawless fish that resemble eels. For many years, they were known only from tooth-like microfossils found in isolation and now called conodont elements. The evolution of mineralized tissues has been

396-594: A geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Werner in his theory of the origin of the Earth, which was developed over the period from 1774 to his death in 1817. The concept became increasingly formalized over time and is now codified in such works as the North American Stratigraphic Code and its counterparts in other regions. Geologic maps showing where various formations are exposed at

462-499: A length that can range from tens of micrometres to 100 micrometres, and spindle-like microfossils can be as long as 50 micrometres. Siliceous ooze is a type of biogenic pelagic sediment located on the deep ocean floor . Siliceous oozes are the least common of the deep sea sediments, and make up approximately 15% of the ocean floor. Oozes are defined as sediments which contain at least 30% skeletal remains of pelagic microorganisms. Siliceous oozes are largely composed of

528-526: A newly designated formation could not be named the Kaibab Formation, since the Kaibab Limestone is already established as a formation name. The first use of a name has precedence over all others, as does the first name applied to a particular formation. As with other stratigraphic units, the formal designation of a formation includes a stratotype which is usually a type section . A type section

594-594: A permanent natural or artificial feature of the geographic area in which they were first described. The name consists of the geographic name plus either "Formation" or a descriptive name. Examples include the Morrison Formation , named for the town of Morrison, Colorado , and the Kaibab Limestone , named after the Kaibab Plateau of Arizona. The names must not duplicate previous formation names, so, for example,

660-1024: A puzzle for more than a century. It has been hypothesized that the first mechanism of chordate tissue mineralization began either in the oral skeleton of conodont or the dermal skeleton of early agnathans . Conodont elements are made of a phosphatic mineral, hydroxylapatite . The element array constituted a feeding apparatus that is radically different from the jaws of modern animals. They are now termed "conodont elements" to avoid confusion. The three forms of teeth (i.e., coniform cones, ramiform bars, and pectiniform platforms) probably performed different functions. For many years, conodonts were known only from enigmatic tooth-like microfossils (200 micrometres to 5 millimetres in length) which occur commonly, but not always in isolation, and were not associated with any other fossil. Conodonts are globally widespread in sediments.Their many forms are considered index fossils , fossils used to define and identify geological periods and date strata. Conodonts elements can be used to estimate

726-853: A sexual cycle but are resistant structures used for survival under unfavourable conditions. Chitinozoa are a taxon of flask -shaped, organic walled marine microfossils produced by an as yet unknown organism. Common from the Ordovician to Devonian periods (i.e. the mid-Paleozoic), the millimetre-scale organisms are abundant in almost all types of marine sediment across the globe. This wide distribution, and their rapid pace of evolution, makes them valuable biostratigraphic markers. Their bizarre form has made classification and ecological reconstruction difficult. Since their discovery in 1931, suggestions of protist , plant , and fungal affinities have all been entertained. The organisms have been better understood as improvements in microscopy facilitated

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792-449: Is not a valid lithological basis for defining a formation. The contrast in lithology between formations required to justify their establishment varies with the complexity of the geology of a region. Formations must be able to be delineated at the scale of geologic mapping normally practiced in the region; the thickness of formations may range from less than a meter to several thousand meters. Geologic formations are typically named after

858-416: Is a bioessential element and is efficiently recycled in the marine environment through the silica cycle . Distance from land masses, water depth and ocean fertility are all factors that affect the opal silica content in seawater and the presence of siliceous oozes. Phytoliths (Greek for plant stones ) are rigid, microscopic structures made of silica , found in some plant tissues and persisting after

924-501: Is a form of calcium carbonate derived from planktonic organisms that accumulates on the sea floor . This can only occur if the ocean is shallower than the carbonate compensation depth . Below this depth, calcium carbonate begins to dissolve in the ocean, and only non-calcareous sediments are stable, such as siliceous ooze or pelagic red clay . Ostracods are widespread crustaceans, generally small, sometimes known as seed shrimps . They are flattened from side to side and protected with

990-416: Is also used informally to describe the odd shapes (forms) that rocks acquire through erosional or depositional processes. Such a formation is abandoned when it is no longer affected by the geologic agent that produced it. Some well-known cave formations include stalactites and stalagmites . Microfossil A microfossil is a fossil that is generally between 0.001 mm and 1 mm in size,

1056-560: Is central to the geologic discipline of stratigraphy , and the formation is the fundamental unit of stratigraphy. Formations may be combined into groups of strata or divided into members . Members differ from formations in that they need not be mappable at the same scale as formations, though they must be lithologically distinctive where present. The definition and recognition of formations allow geologists to correlate geologic strata across wide distances between outcrops and exposures of rock strata . Formations were at first described as

1122-479: Is divided between classifying them as polychaetes and regarding it as unsafe to classify them as members of any broader grouping. In 2020, a new study showed the presence of Nephrozoan type guts , the oldest on record, supporting the bilaterian interpretation. Cloudinids are important in the history of animal evolution for two reasons. They are among the earliest and most abundant of the small shelly fossils with mineralized skeletons , and therefore feature in

1188-512: Is entirely artificial, it is not without merit, as the form taxa show traits similar to those of genuine taxa — for example the ' explosion ' in the Cambrian and the mass extinction at the end of the Permian . Acritarch diversity reflects major ecological events such as the appearance of predation and the Cambrian explosion . Precambrian marine diversity was dominated by acritarchs. They underwent

1254-477: Is first found in the fossil record in the late Devonian period, but at that time it is indistinguishable from spores. It increases in abundance until the present day. A spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants , algae , fungi and protozoa . Bacterial spores are not part of

1320-488: Is formed from, or contains a high proportion of, calcium carbonate in the form of calcite or aragonite . Calcareous sediments ( limestone ) are usually deposited in shallow water near land, since the carbonate is precipitated by marine organisms that need land-derived nutrients. Generally speaking, the farther from land sediments fall, the less calcareous they are. Some areas can have interbedded calcareous sediments due to storms, or changes in ocean currents. Calcareous ooze

1386-455: Is ideally a good exposure of the formation that shows its entire thickness. If the formation is nowhere entirely exposed, or if it shows considerably lateral variation, additional reference sections may be defined. Long-established formations dating to before the modern codification of stratigraphy, or which lack tabular form (such as volcanic formations), may substitute a type locality for a type section as their stratotype. The geologist defining

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1452-476: Is likely that most acritarch species from the Paleozoic represent various stages of the life cycle of algae that were ancestral to the dinoflagellates . The nature of the organisms associated with older acritarchs is generally not well understood, though many are probably related to unicellular marine algae . In theory, when the biological source (taxon) of an acritarch does become known, that particular microfossil

1518-506: Is produced in huge quantities. There is an extensive fossil record of pollen grains, often disassociated from their parent plant. The discipline of palynology is devoted to the study of pollen, which can be used both for biostratigraphy and to gain information about the abundance and variety of plants alive — which can itself yield important information about paleoclimates. Also, pollen analysis has been widely used for reconstructing past changes in vegetation and their associated drivers. Pollen

1584-637: Is removed from the acritarchs and classified with its proper group. Acritarchs were most likely eukaryotes . While archaea, bacteria and cyanobacteria ( prokaryotes ) usually produce simple fossils of a very small size, eukaryotic unicellular fossils are usually larger and more complex, with external morphological projections and ornamentation such as spines and hairs that only eukaryotes can produce; as most acritarchs have external projections (e.g., hair, spines, thick cell membranes, etc.), they are predominantly eukaryotes, although simple eukaryote acritarchs also exist. Acritarchs are found in sedimentary rocks from

1650-471: Is represented in the microfossil record, the most abundant forms are protist skeletons or microbial cysts from the Chrysophyta , Pyrrhophyta , Sarcodina , acritarchs and chitinozoans , together with pollen and spores from the vascular plants . A microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by

1716-534: Is unknown, Cloudinids comprise two genera: Cloudina itself is mineralized, whereas Conotubus is at best weakly mineralized, whilst sharing the same "funnel-in-funnel" construction. Cloudinids had a wide geographic range, reflected in the present distribution of localities in which their fossils are found, and are an abundant component of some deposits. Cloudina is usually found in association with microbial stromatolites , which are limited to shallow water, and it has been suggested that cloudinids lived embedded in

1782-567: The Isle of Bute . 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. Formation (geology) A formation must be large enough that it can be mapped at the surface or traced in

1848-441: The formation of the Earth 4.54 billion years ago. Nonetheless, life may have started even earlier, at nearly 4.5 billion years ago, as claimed by some researchers. Index fossils , also known as guide fossils, indicator fossils or dating fossils, are the fossilized remains or traces of particular plants or animals that are characteristic of a particular span of geologic time or environment, and can be used to identify and date

1914-416: The microbial mats , growing new cones to avoid being buried by silt. However no specimens have been found embedded in mats, and their mode of life is still an unresolved question. The classification of the cloudinids has proved difficult: they were initially regarded as polychaete worms, and then as coral-like cnidarians on the basis of what look like buds on some specimens. Current scientific opinion

1980-772: The "father of modern oceanography", who proposed the term radiolarian ooze for the silica deposits of radiolarian shells brought to the surface during the Challenger expedition . A biogenic ooze is a pelagic sediment containing at least 30 per cent from the skeletal remains of marine organisms. The study of microfossils is called micropaleontology . In micropaleontology, what would otherwise be distinct categories are grouped together based solely on their size, including microscopic organisms and minute parts of larger organisms. Numerous sediments have microfossils, which serve as significant biostratigraphic , paleoenvironmental , and paleoceanographic markers. Their widespread presence around

2046-648: The 350 described freshwater dinoflagellate species, and in about 10% of the known marine species. Dinocysts have a long geological record with geochemical markers suggest a presence that goes back to the Early Cambrian . Spicules are structural elements found in most sponges . They provide structural support and deter predators . The meshing of many spicules serves as the sponge's skeleton , providing structural support and defense against predators. Smaller, microscopic spicules can become microfossils, and are referred to as microscleres . Larger spicules visible to

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2112-558: The Ballagan Formation, such as Berwick-upon-Tweed Barrow Scar (near Alwinton ), and a borehole core at Norham . 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. Diverse assemblages of fish teeth and other microfossils have been found at Ayrshire and at Hawk's Nib and Mill Hole, on

2178-418: The containing rocks. To be practical, index fossils must have a limited vertical time range, wide geographic distribution, and rapid evolutionary trends. Rock formations separated by great distances but containing the same index fossil species are thereby known to have both formed during the limited time that the species lived. Index fossils were originally used to define and identify geologic units, then became

2244-714: The correlation of rock units. Microfossils are found in rocks and sediments as the microscopic remains of what were once life forms such as plants, animals, fungus, protists, bacteria and archaea. Terrestrial microfossils include pollen and spores . Marine microfossils found in marine sediments are the most common microfossils. Everywhere in the oceans, microscopic protist organisms multiply prolifically, and many grow tiny skeletons which readily fossilise. These include foraminifera , dinoflagellates and radiolarians . Palaeontologists (geologists who study fossils) are interested in these microfossils because they can use them to determine how environments and climates have changed in

2310-554: The debate about why such skeletons first appeared in the Late Ediacaran. The most widely supported answer is that their shells are a defense against predators, as some Cloudina specimens from China bear the marks of multiple attacks, which suggests they survived at least a few of them. The holes made by predators are approximately proportional to the size of the Cloudina specimens, and Sinotubulites fossils, which are often found in

2376-439: The decay of the plant. These plants take up silica from the soil, whereupon it is deposited within different intracellular and extracellular structures of the plant. Phytoliths come in varying shapes and sizes. The term "phytolith" is sometimes used to refer to all mineral secretions by plants, but more commonly refers to siliceous plant remains. The term calcareous can be applied to a fossil, sediment, or sedimentary rock which

2442-550: The essential geologic time markers, based on their relative ages and the law of superposition . The divisions of the geological time scale were described and put in chronological order by the geologists and stratigraphers of the 18th and 19th centuries. Geologic formations can be usefully defined for sedimentary rock layers, low-grade metamorphic rocks , and volcanic rocks . Intrusive igneous rocks and highly metamorphosed rocks are generally not considered to be formations, but are described instead as lithodemes . "Formation"

2508-522: The formation is expected to describe the stratotype in sufficient detail that other geologists can unequivocally recognize the formation. Although formations should not be defined by any criteria other than primary lithology, it is often useful to define biostratigraphic units on paleontological criteria, chronostratigraphic units on the age of the rocks, and chemostratigraphic units on geochemical criteria, and these are included in stratigraphic codes. The concept of formally defined layers or strata

2574-457: The fossil record by these dinocysts, typically 15 to 100 micrometres in diameter, which accumulate in sediments as microfossils. Organic-walled dinocysts have resistant cell walls made out of dinosporin . There are also calcareous dinoflagellate cysts and siliceous dinoflagellate cysts . Dinocysts are produced by a proportion of dinoflagellates as a dormant , zygotic stage of their lifecycle. These dinocyst stages are known to occur in 84 of

2640-405: The fossils used must be widespread geographically, so that they can be found in many different places. They must also be short lived as a species, so that the period of time during which they could be incorporated in the sediment is relatively narrow. The longer lived the species, the poorer the stratigraphic precision, so fossils that evolve rapidly. Often biostratigraphic correlations are based on

2706-476: The genus Nummulites . In 2017, fossilized microorganisms , or microfossils, were discovered in hydrothermal vent precipitates in the Nuvvuagittuq Belt of Quebec, Canada that may be as old as 4.28 billion years old, the oldest record of life on Earth , suggesting "an almost instantaneous emergence of life" (in a geological time-scale), after ocean formation 4.41 billion years ago , and not long after

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2772-699: The largest exposures of the Ballagan Formation occur along the coastal end cliffs of Burnmouth . Tetrapod, fish, and arthropod fragments are common in several layers at Burnmouth, not just in fine-grained overbank deposits but also coarse river channel conglomerates , an unusual mode of preservation. Tetrapod fossils have been found in the vicinity of Tantallon Castle . Additional Midland Valley sites include Crumble Edge (along Whiteadder Water ), Coldstream , Cockburnspath , Cove (in Berwickshire ), and Whitrope Burn (near Hawick ). A few locales in nearby Northumberland , England encompass fossil-bearing outcrops of

2838-423: The late Ediacaran period about 550 million years ago, and became extinct at the base of the Cambrian . They formed small millimetre size conical fossils consisting of calcareous cones nested within one another; the appearance of the organism itself remains unknown. The name Cloudina honors Preston Cloud . Fossils consist of a series of stacked vase-like calcite tubes, whose original mineral composition

2904-464: The main evidence of polychaetes in the geological past, and the only way to restore the evolution of this important group of animals. Small size of scolecodonts, usually less than 1 mm, puts them into a microfossil category. They are common by-product of conodont, chitinozoan and acritarch samples, but sometimes they occur in the sediments where other fossils are very rare or absent. The cloudinids were an early metazoan family that lived in

2970-762: The middle formation of the Inverclyde Group . This change was motivated by the recognition that the youngest parts of the Devonian Upper Old Red Sandstone (now known as the Kinnesswood Formation ) were geologically continuous with the lowest parts of the Lower Carboniferous Calciferous Sandstone Measures (now known as the Ballagan and Clyde Sandstone formations). This interval of Devonian-Carboniferous overlap

3036-495: The naked eye are called megascleres . Spicule can be calcareous , siliceous , or composed of spongin . They are found in a range of symmetry types. Sediments at the bottom of the ocean have two main origins, terrigenous and biogenous. Terrigenous sediments account for about 45% of the total marine sediment, and originate in the erosion of rocks on land, transported by rivers and land runoff, windborne dust, volcanoes, or grinding by glaciers. Biogenous sediments account for

3102-477: The naked eye. A commonly applied cutoff point between "micro" and "macro" fossils is 1 mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores ) or component parts (such as small teeth or spores ) of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in

3168-415: The order Eunicida - a diverse and abundant group of worms which has been inhabiting different marine environments in the past 500 million years. Composed of highly resistant organic substance, the scolecodonts are frequently found as fossils from the rocks as old as the late Cambrian . Since the worms themselves were soft-bodied and hence extremely rarely preserved in the fossil record, their jaws constitute

3234-527: The organic material kerogen as the cell breaks down after death. Kerogen is insoluble in mineral acids , bases , and organic solvents . Over time, it is mineralised into graphite or graphite-like carbon , or degrades into oil and gas hydrocarbons. There are three main types of cell morphologies. Though there is no established range of sizes for each type, spheroid microfossils can be as small as about 8  micrometres , filamentous microfossils have diameters typically less than 5 micrometres and have

3300-400: The organism was incompletely known, and the strata extend the known fossil range. If the fossil is easy to preserve and easy to identify, more precise time estimating of the stratigraphic layers is possible. Microfossils can be classified by their composition as: (a) siliceous , as in diatoms and radiolaria , (b) calcareous , as in coccoliths and foraminifera , (c) phosphatic , as in

3366-410: The other 55% of the total sediment, and originate in the skeletal remains of marine protists (single-celled plankton and benthos microorganisms). Much smaller amounts of precipitated minerals and meteoric dust can also be present. Ooze , in the context of a marine sediment, does not refer to the consistency of the sediment but to its biological origin. The term ooze was originally used by John Murray ,

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3432-490: The past, and where oil and gas can be found today. Some microfossils are formed by colonial organisms such as Bryozoa (especially the Cheilostomata ), which have relatively large colonies but are classified by fine skeletal details of the small individuals of the colony. As another example, many fossil genera of Foraminifera , which are protists are known from shells (called tests ) that were as big as coins, such as

3498-896: The present back into the Archean . They are typically isolated from siliciclastic sedimentary rocks using hydrofluoric acid but are occasionally extracted from carbonate-rich rocks. They are excellent candidates for index fossils used for dating rock formations in the Paleozoic Era and when other fossils are not available. Because most acritarchs are thought to be marine (pre-Triassic), they are also useful for palaeoenvironmental interpretation. The Archean and earliest Proterozoic microfossils termed "acritarchs" may actually be prokaryotes. The earliest eukaryotic acritarchs known (as of 2020) are from between 1950 and 2150 million years ago. Recent application of atomic force microscopy , confocal microscopy , Raman spectroscopy , and other analytic techniques to

3564-432: The same beds, have so far shown no such holes. These two points suggest that predators attacked in a selective manner, and the evolutionary arms race which this indicates is commonly cited as a cause of the Cambrian explosion of animal diversity and complexity. Some dinoflagellates produce resting stages , called dinoflagellate cysts or dinocysts , as part of their lifecycles. Dinoflagellates are mainly represented in

3630-423: The seasons. Acritarchs , Greek for confused origins , are organic-walled microfossils, known from about 2,000  million years ago to the present. Acritarchs are not a specific biological taxon, but rather a group with uncertain or unknown affinities. Most commonly they are composed of thermally altered acid insoluble carbon compounds ( kerogen ). While the classification of acritarchs into form genera

3696-441: The silica based skeletons of microscopic marine organisms such as diatoms and radiolarians . Other components of siliceous oozes near continental margins may include terrestrially derived silica particles and sponge spicules. Siliceous oozes are composed of skeletons made from opal silica Si(O 2 ) , as opposed to calcareous oozes , which are made from skeletons of calcium carbonate organisms (i.e. coccolithophores ). Silica (Si)

3762-498: The southeast corner of Scotland. One of the earliest sites to be studied was the fish bed at Foulden , which hosts many well-preserved fish fossils, notably including endemic actinopterygians (ray-finned fish) and the first complete skeleton of a rhizodont . Plants and arthropods also form a significant portion of Foulden fossils. This site and its fish fossils were publicized by E.I. White in 1927, and further excavations were performed by Stan Wood in 1980-1981. The Foulden fish bed

3828-438: The study of some vertebrates , or (d) organic , as in the pollen and spores studied in palynology . This division focuses on differences in the mineralogical and chemical composition of microfossil remains rather than on taxonomic or ecological distinctions. Pollen has an outer sheath, called a sporopollenin , which affords it some resistance to the rigours of the fossilisation process that destroy weaker objects. It

3894-432: The study of the ultrastructure, life history, and systematic affinities of mineralized, but originally organic-walled microfossils, have shown some acritarchs are fossilized microalgae . In the end, it may well be, as Moczydłowska et al. suggested in 2011, that many acritarchs will, in fact, turn out to be algae. Cells can be preserved in the rock record because their cell walls are made of proteins which convert to

3960-572: The study of their fine structure, and it has been suggested that they represent either the eggs or juvenile stage of a marine animal. However, recent research has suggested that they represent the test of a group of protists with uncertain affinities. The ecology of chitinozoa is also open to speculation; some may have floated in the water column, where others may have attached themselves to other organisms. Most species were particular about their living conditions, and tend to be most common in specific paleoenvironments. Their abundance also varied with

4026-407: The subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of

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4092-643: The surface are fundamental to such fields as structural geology , allowing geologists to infer the tectonic history of a region or predict likely locations for buried mineral resources. The boundaries of a formation are chosen to give it the greatest practical lithological consistency. Formations should not be defined by any criteria other than lithology. The lithology of a formation includes characteristics such as chemical and mineralogical composition, texture, color, primary depositional structures , fossils regarded as rock-forming particles, or other organic materials such as coal or kerogen . The taxonomy of fossils

4158-464: The temperatures rocks have been exposed to, which allows the thermal maturation levels of sedimentary rocks to be determined, which is important for hydrocarbon exploration . Conodont teeth are the earliest vertebrate teeth found in the fossil record, and some conodont teeth are the sharpest that have ever been recorded. Scolecodonts ( worm jaws in Latin) are tiny jaws of polychaete annelids of

4224-597: The visual study of which requires the use of light or electron microscopy . A fossil which can be studied with the naked eye or low-powered magnification, such as a hand lens, is referred to as a macrofossil . Microfossils are a common feature of the geological record , from the Precambrian to the Holocene . They are most common in deposits of marine environments, but also occur in brackish water, fresh water and terrestrial sedimentary deposits. While every kingdom of life

4290-680: Was named the Inverclyde Group, and the cementstone -rich "drab beds" in the middle of the group were renamed to the Ballagan Formation. In Lothian , the Ballagan and Clyde Sandstone formations are sometimes known as the Tyninghame Formation . Many localities of the Ballagan Formation preserve exceptional fossils. The majority of fossiliferous sites are in the Midland Valley (particularly the Scottish Borders and East Lothian ), in

4356-617: Was the primary theme for volume 76 of the Transactions of the Royal Society of Edinburgh: Earth Sciences journal, published in 1985. 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. Willie's Hole has continued to produce well-preserved fossils of arthropods , fish, and partial tetrapod skeletons. By far

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