Making of a Land - Chapter 5

Illustraiones chapter 5.

Illustrations can be downloaded in the gallery further down.

 

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Chapter 05 - p. 148-149

Limestone boulder from Langøya, off Holmestrand, showing a rich variety of Silurian fossils, including corals, brachiopods and bryozoans. (Photo: H.A. Nakrem)

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Chapter 05 - p.153a

Folding of the Cambro-Silurian strata is a result of the collision between Baltica and the American Plate, Laurentia, when the Caledonides were formed in the west. This deformation was quite strong in places, as here in Ordovidian shales at Bygdøy in Oslo. (Photo: D. Worlsey)

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Chapter 05 - p. 153b

Simplified geological map of the Oslo region showing the distribution of Cambro-Silurian sedimentary rocks and Permo-Carboniferous magmatic rocks, as well as the most importen faults. 

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Chapter 05 - p. 154a

Life in the Cambrian. Trilobites which crawled on the bottom and swam in the sea are typical representatives of organisms in the Early Cambrian marine environment on Baltica. In other parts of the world, reefs dominated by sponges (in the foreground) have been found, but no such reefs are known in Norway. (Reproduced by permission of the Natural History Muesum, University of Oslo. Illustration: B. Bocianowski)

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Chapter 05 - p. 154b

Trilobites were among the first organisms to evolve a hard shell (exoskeloton)

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Chapter 05 - p. 155-1

Holmia kjerulfi, a trilobite from the Lower Cambrian (Holmlia shale), Ringsaker (2 cm long). (Photo: H.A. Nakrem)

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Chapter 05 - p. 155-2

Fossils from Cambrian deposits in the Oslo region
A. The mikrofossil Torellella, Hadeland (Photo: H.A. Nakrem)
B. The mikrofossil Lapworthellide, Hadeland. (Photo: H.A. Nakrem)
C. The mikrofossil Lapworthellide, Hadeland (Photo: H.A. Nakrem)
D.The trilobite Ptychagnostus gibbus, Slemmestad. (Photo D: M. Høyberget/ D.L. Bruton)

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Chapter 05 - p. 155a

The mikrofossil Torellella, Hadeland (Photo: H.A. Nakrem)

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Chapter 05 - p. 155b

The mikrofossil Lapworthellide, Hadeland. (Photo: H.A. Nakrem)

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Chapter 05 - p. 155c

The mikrofossil Lapworthellide, Hadeland (Photo: H.A. Nakrem)

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Chapter 05 - p. 155d

The trilobite Ptychagnostus gibbus, Slemmestad. (Photo D: M. Høyberget/ D.L. Bruton)

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Chapter 05 - p. 156a

Life in the Ordovician was characterised by cephalopods and graptolites in the water masses and sea lilies, trilobites and corals on the sebaed. (Reproduced by permission of the Natural History Muesum, University of Oslo. Illustration: B. Bocianowski)

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Chapter 05 - p. 156b

Asaphus expansus, the trilobite which W.C. Brøgger illustrated in his work: "Die silurischen Etagen 2 und 3" from 1882. From the Hukf Formation, Tøyen, Oslo. 8 cm long. (Photo: H.A. Nakrem)

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Chapter 05 - p. 157

Fossils from Ordovician deposits in the Oslo region 
A. The graptolite Rhabdinopora, Tøyen Formation, Tøyen (Oslo) (Photo: H.A. Nakrem)
B. The graptolite Phyllograptus, Tøyen Formation, Slemmestad (Photo: H.A. Nakrem)
C. The starfish Cnemidactis osloensis, Elnesformasjonen, Djuptrekkodden (Asker), ca. 4 cm in diameter (Foto C: D.L. Bruton / T. Hansen)
D. The trilobite Pseudomegalaspis, Elnes Formation, Fiskum (Photo: H.A. Nakrem)
E. The cephalopod Endoceras (upside down on the bedding plane), Hukformasjonen, Krekling i Buskerud, 4 cm in diameter. (Photo: H.A. Nakrem)
F. The cephalopod Discoceras, Bønsnes Formation (Upper Ordovician), Stavnestangen (Ringerike), 12 cm in diameter. (Photo: H.A. Nakrem)

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Chapter 05 - p. 157a

The graptolite Rhabdinopora, Tøyen Formation, Tøyen (Oslo) (Photo: H.A. Nakrem)

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Chapter 05 - p. 157b

The graptolite Phyllograptus, Tøyen Formation, Slemmestad (Photo: H.A. Nakrem)

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Chapter 05 - p. 157c

The starfish Cnemidactis osloensis, Elnesformasjonen, Djuptrekkodden (Asker), ca. 4 cm in diameter (Foto C: D.L. Bruton / T. Hansen)

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Chapter 05 - p. 157d

The trilobite Pseudomegalaspis, Elnes Formation, Fiskum (Photo: H.A. Nakrem)

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Chapter 05 - p. 157e

The cephalopod Endoceras (upside down on the bedding plane), Hukformasjonen, Krekling i Buskerud, 4 cm in diameter. (Photo: H.A. Nakrem)

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Chapter 05 - p. 157f

The cephalopod Discoceras, Bønsnes Formation (Upper Ordovician), Stavnestangen (Ringerike), 12 cm in diameter. (Photo: H.A. Nakrem)

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Chapter. 05 - p. 158

A. Crinoids (1.5 m in diameter) curled on a bedding plane, Vik Formation, Malmøya. (Photo: H.A. Nakrem)
B. Crinoid, holdfast ("root"), ca. 20 cm i diameter, Rytteråker Formation, Malmøya. (Photo: H.A. Nakrem)
C. Favosites, honeycomb coral (arrow) in cross section (field of view is 25 cm wide), Vik Formation, Malmøya. (Photo: H.A. Nakrem) 
D. Bedding plane with several corals, Steinsfjorden Formation, Langøya near Holmestrand. (Photo: H.A. Nakrem)
E. Monograptus, a graptolite, Skinnerbukt Formation, Malmøya. (Photo: H.A. Nakrem)
F. Bedding plane with various brachiopods, including Eoplectodonta, Isorthis and Coolina, Solvik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158a

Crinoids (1.5 m in diameter) curled on a bedding plane, Vik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158b

Crinoid, holdfast ("root"), ca. 20 cm i diameter, Rytteråker Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158c

Favosites, honeycomb coral (arrow) in cross section (field of view is 25 cm wide), Vik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158d

Bedding plane with several corals, Steinsfjorden Formation, Langøya near Holmestrand. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158e

Monograptus, a graptolite, Skinnerbukt Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 158f

Bedding plane with various brachiopods, including Eoplectodonta, Isorthis and Coolina, Solvik Formation, Malmøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 159

The graptolite Didymograptus from the Tøyen Formation, Lower Ordovician, Slemmestad, 4 cm long. This type of graptolite is very common in Ordovcian lihologies over large areas, and is therefore a valuable zone fossil. (Photo: H.A. Nakrem)

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Chapter 05 - p. 160

Thalassinoides, burrows probably excavated by a crustacean or similar articulated animal living in the sea bottom.  (Illustration: G. Pemberton)

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Chapter 05 - p. 161a

A landscape from the end of the Silurian, when the first plants began to grow on land. Sea scorpions soon began to creep out of the sea too, and land scorpions, millipedes and mites settled on land, where the plants gave food and protection from the sun. (Reproduced by permission of the Natural History Muesum, University of Oslo. Illustration: B. Bocianowski)

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Chapter 05 - p. 161b

Pharyngolepis, one of the jawless fish found as a fossil in Ringerike. (Illustrasjon: NHM, UiO)

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Chapter 05 - p. 162

One of the finest fossils found in Norway, the 75 cm long sea scorpion, Mixopterus kiaeri, found in red sandstone near Kroksund, Ringerike. When Johan A. Kiær described the discovery in 1924 he wrote: "I'll never forget the moment when we found this new scorpion. My assistants had just turned over a large flat stone when we saw the big creature with its outstretched flippers. It looked so natural we almost expected it to get up from the spot where it had been resting for so many millions of years and creep down to the lake below us.". (Foto: P. Aas, NHM, UiO)

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Chapter 05 - p. 163

Nodules and trace fossils
A. Calcareous nodules in dark shale from Hovedøya (Skogerholmen Formation, Ordovicioan). (Photo: H.A.Nakrem)
B. Cross section of nodules and some fossil fragments, a coral and some crinoid stems in and around the nodules (Rytteråker Formation, Silurian, Malmøya), field of view is 30 cm (Photo: H.A.Nakrem)
C. Nodules in the form of burrows (Rytteråker Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)
D. Cambrian cannonballs (Alum Shale Formation, Slemmestad). (Photo: H.A.Nakrem)
E. Bedding plane with fine grazing burrows (Chondrites type) (Solvik Formation, Sillurian, Malmøya), the burrows are about 2 mm in diameter. (Photo: H.A.Nakrem)
F. Weathered bedding plane which shows a maze of coarse burrows (Vik Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 163a

Calcareous nodules in dark shale from Hovedøya (Skogerholmen Formation, Ordovicioan). (Photo: H.A.Nakrem)

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Chapter 05 - p. 163b

Cross section of nodules and some fossil fragments, a coral and some crinoid stems in and around the nodules (Rytteråker Formation, Silurian, Malmøya), field of view is 30 cm (Photo: H.A.Nakrem)

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Chapter 05 - p. 163c

Nodules in the form of burrows (Rytteråker Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 163d

Cambrian cannonballs (Alum Shale Formation, Slemmestad). (Photo: H.A.Nakrem)

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Chapter 05 - p. 163e

Bedding plane with fine grazing burrows (Chondrites type) (Solvik Formation, Sillurian, Malmøya), the burrows are about 2 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 163f

Weathered bedding plane which shows a maze of coarse burrows (Vik Formation, Silurian, Malmøya), the burrows are 10–20 mm in diameter. (Photo: H.A.Nakrem)

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Chapter 05 - p. 164

Generalised stratigraphical table showing the division of the Cambro-Silurian succession and characteristic aspects in the central part of the Oslo region (Oslo-Asker)

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Chapter 05 - p. 165

Black Middle Cambrian shales lie directly on Precambrian basement and are overlain by a horizontal intrusive sill og light maenaite at Slemmstad, in the centre of the Oslo region. (Photo: H.A. Nakrem)

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Chapter 05 - p. 166

Large Lower Ordovician carbonate "cannonballs" are exposed in the Alum Shale at Nærsnes, Near Slemmestad. (Photo: B.T. Larsen)

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Chapter 05 - p. 167a

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Early Cambrian ( ca. 540 million years ago).

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Chapter 05 - p. 167b

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Middle Cambrian (ca. 500–510 million years ago).

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Chapter 05 - p. 167c

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Early-middle Ordovician (ca. 470–480 million years ago). 

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Chapter 05 - p. 167d

Schematic block diagrams showing the Cambrian and Ordovician depositional development of the Oslo region
Late Ordovician (ca. 443–445 million years ago). 

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Chapter 06 - p. 169

A greenish, readily weatering layer of bentonite (fossil volcanic ash), approximately 1 m thick, is found withhin dark Odovician shales of the Arnestad Formation in Asker. (Photo: H.A. Nakrem)

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Chapter 05 - P. 170

Tidal channel filled with boulders of calcareous sandstone uppermost in the Ordovician (the Langøyene Formation) on Kalvøya. (Photo: H.A. Nakrem)

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Chapter 05 - p. 171a

The Ordovician Tromsdal limestone is quarried in Verdal, Nord- Trøndelag. (Photo: H.A. Nakrem)

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Chapter 05 - p. 171b

The cliff of Tsjebysjovfjellet on the south side of Hornsund, Svalbard. The rocks are almost unmetamorphosed carbonates in Nørdstetind Formation, which is part of the Ordovician Sørkapp Land Group. The recumbent isoclinal fold is of Caledonian age and is probably a folded nappe. (Photo:W. Dallmann)

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Chapter 05 - p. 171c

Distribution of Cambro-Silurian rocks (black) in Norway and adjacent part of western Sweden. (From: H. Fossen)

 

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Chapter 05 - p. 172

Cambro-Silurian fossils from localities outside the Oslo region
A. Rhabdinopora, an Ordovician graptolite, Digermul Peninsula, Finnmark (field of view is 6 mm wide). (Photo: H.A. Nakrem)
B. Syringophyllum, a coral in metamorphosed and deformed Silurian limestone (marble), Bergen (the coral is 3 mm in diameter). (Photo: H.A. Nakrem)
C. Peltocare compactum, an Ordovician trilobite, Digermul Peninsula, Finnmark (ca. 12 mm long). (Photo: H.A. Nakrem)
D. Drill core showing brachiopods and corals, from the Farsund Basin (Lower Silurian), Skagerrak (the core is 5 cm in diameter). (Photo: H.A. Nakrem)
E. Deformed trilobite Calymene, Silurian, Bergen (Reusch's original specimen), (the trilobite is 1 cm across). (Photo: H.A. Nakrem)
F. Solidary corals ("Cyathophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The corals are 1 cm in diameter). (Photo: H.A. Nakrem)
G. Colonial corals ("Syringophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The coral is 3 mm in diameter). (Photo: H.A. Nakrem)
H. Gonioceras, a cephalopod from the Ordovician on Bjørnøya (25 cm long) (Photo: H.A. Nakrem)

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Chapter 05 - p. 172a

Rhabdinopora, an Ordovician graptolite, Digermul Peninsula, Finnmark (field of view is 6 mm wide). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172b

Syringophyllum, a coral in metamorphosed and deformed Silurian limestone (marble), Bergen (the coral is 3 mm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172c

Peltocare compactum, an Ordovician trilobite, Digermul Peninsula, Finnmark (ca. 12 mm long). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172d

Drill core showing brachiopods and corals, from the Farsund Basin (Lower Silurian), Skagerrak (the core is 5 cm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172e

Deformed trilobite Calymene, Silurian, Bergen (Reusch's original specimen), (the trilobite is 1 cm across). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172f

Solidary corals ("Cyathophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The corals are 1 cm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172g

Colonial corals ("Syringophyllum") in metamorphosed and deformed Silurian limestone (marble), Bergen (The coral is 3 mm in diameter). (Photo: H.A. Nakrem)

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Chapter 05 - p. 172h

Gonioceras, a cephalopod from the Ordovician on Bjørnøya (25 cm long) (Photo: H.A. Nakrem)

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Chapter 05 - p. 173a

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Early Silurian (ca. 435–440 million years ago). 

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Chapter 05 - p. 173b

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Early Silurian (ca. 430 million years ago). 

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Chapter 05 - p. 173c

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Middle Silurian (ca. 430–425 million years ago).

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Chapter 05 - p. 173d

Schematic block diagrams showing the Silurian depositional development of the Oslo region.
Late Silurian (ca. 420 million years ago). 

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Chapter 05 - p. 174

A. Relatively flat reef structure (1 m thick) in the upper part of the Rytteråker Formation at Limovnstangen, Ringerike. The yellow broken line denote the reef surface, the red one its base and the blue one the reef flank. 
B. Reef-building coral: Halysites (chain coral)
C. Reef-building coral: Favosites (honeycomb coral)
(Photos: H.A. Nakrem)

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Chapter 05 - p. 174b

Reef-building coral: Halysites (chain coral) (Photo: H.A. Nakrem)

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Chapter 05 - p. 174c

Reef-building coral: Favosites (honeycomb coral) (Photo: H.A. Nakrem)

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Chapter 05 - p. 175

Sediments and reconstructed depositional environment from the end of the Silurian period

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Chapter 05 - p. 175a

The shift from green, coastal sandstone to red, continental sandstone in Ringerike, with wave ripples in the red beds, probably formed in a lake or lagoon with fresh or brackish water. Kroksund, Ringerike. (Photo: H.A. Nakrem)

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Chapter 05 - p. 175b

A river channel has cut down into more fine-grained fluvial sediment. Ringerike Sandstone, Sundvollen, Ringerike. (Photo: D. Worsley)

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Chapter 05 - p. 175c

Model of the sea scorpion, Mixopterus kiaeri, in its natural habitat in these lakes. (Natural History Museum, University of Oslo. Foto: H.A. Nakrem)

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Chapter. 05 - p. 175d

Model of the primitive fish, Aceraspis, which lived with the sea scorpions. (Natural History Museum, University of Oslo. Photo: H.A. Nakrem)

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Chapter. 05 - p. 176 

Paleogeographical map of Baltica at the transition from Early to Late Silurian: the Caledonides were rising in the north and west, while the southern margin of Baltica formed a deep foreland basin towards the Palaeotethys Ocean. (Illustration: T. Torsvik)

 

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Chapter 05 - p. 177a 

Life in a fossil reef reconstructed and modellen on the basis of the reef at Limovnstangen, Ringerike. The reef was primarily built up of corals (B,D,I,K,L) and calcareous sponges (stromatoporoids) (A), but brachiopods (F), bryozoans (G), gastropods (C), algae and sea lillies (H) were all important components in this environment. Trilobites crawled among the sedentary organisms, while cephalopods (J) swam in the sea surronding the reef. (NHM, UiO. foto H.A. Nakrem)

 

 

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