PALEOZOIC TIME — LOWER SILURIAN. 521 



land and the areas to the south and southeast, which could have made its fauna more 

 American than British, must have had great length. According to Etheridge, the Lower 

 Silurian of Great Britain, up to 1885, had afforded 161 species of Hydrozoans, 47 of 

 Actinozoans, 5 of Crinoids, 23 of Cystoids, 6 of Asterioids, 174 of Brachiopods, 1« of Bryo- 

 zoans, 80 of Lamellibranchs, 19 of Pteropods, 67 of Gastropods, 21 of Heteropods, 66 of 

 Cephalopods, 188 of Trilobites, 31 of Entomostracan and Phyllopod Crustaceans ; no 

 Eurypterids, no Insects, no Fishes. 



Scandinavia and Russia adjoining. — The area of metamorphic — mostly Archsean 

 — rocks covers, besides the Scandinavian peninsula, the country to and including the 

 White Sea and thence southwest to the Gulf of Einland, thus inclosing entirely the Gulf 

 of Bothnia. The Cambro-Silurian borders this region at the North Cape ; also north of 

 St. Petersburg and south of this place westward along the south side of the Gulf of Fin- 

 land to the Swedish islands of Gotland and Oland in the Baltic, and the adjoining east 

 coast of Sweden. Then, over the interior of Scandinavia, there is a large area on the west 

 side of the mountains from above Trondhjem to the shores south of Bergen ; and east of 

 the mountains about Ostersund and Christiania, and also at some other points. The beds 

 have in general a thickness of from 1000' to 2000'. There are in Finland, Stage B (the 

 first) , Graptolitic beds containing Lingula, Siphonotreta, Oholus, the limestones contain- 

 ing ilfep'aZaspis, Orthis {O.parva)., Ortlioceras, Poramhonites, AsaiJlms, Ceraurus , Ampyx, 

 Fhacops; in Stage C, Echinosphmrites, Orthoceras ; and above, Orthis (0. lynx), Poram- 

 bonites, Pleurotomaria, Ceraurus, Phacops ; Stage D, with Strophomena, Lichas, Ceraurus, 

 Phacops (Chasmops) ; Stage E, with Leptoena {L. sericea), Strophomena (S. deltoidea), 

 Orthis (0. testudinarin) , Phacops, Encrinurus, Cybele; Stage F, with Orthis, Strophomena 

 (S. expansa), Bellerophon {B. bilobatus), Phacops, Ceraurus, Encrinurus. 



France. — The Armorican sandstone of Brittany afforded Lebesconte and Barrels : 

 3 Trilobites ; only 4 Brachiopods, and those of the Lingula family ; over 30 Lamellibranchs, 

 a Bucania, and 3 Ceratiocarids, — but a poor representation of the fauna of the period, 

 because of the impurity in the waters which a sandstone formation indicates. Barrois 

 refers the beds to the age of the Chazy and Trenton limestones of the United States. The 

 Ceratiocarids include : Ceratiocaris, Myocaris lutsaria Salter and Trigonocaris Lebes- 

 contei Barrois. The Lower Silurian rocks of Portugal have afforded a very large Trilo- 

 bite of the genus Lichas. It is named Lichas ( Uralichas) Eibeiroi. The total length is 

 estimated to be 560 mm., and 385 mm. without the caudal spine, which is 175 mm. long. 

 {Comm. des Trav. Q-eol. du Portugal, Fauna Silurica, Lisbon, 1892.) This is the longest 

 Trilobite described ; it exceeds 2 feet in length. Paradoxides regina, described by 

 Matthew from the Cambrian of New Brunswick, was estimated to have a total length 

 of 450 mm. 



Bohemia. — The Lower Silurian of Bohemia is divided by Barrande into 5 sections. 

 They afford Trilobites of the following genera. (The numbers in parentheses show in 

 which of the 5 sections they occur ; and the — and + , that the genus had species also in 

 preceding or later time.) Agnostus (+1, 5), Acidasjris (1 to 5+), ^glina (1 to 5), 

 Amphion (1), Ampyx (5 + ),Areia (2, 5), Arethusina (4 + ), Asaphus (1 to 5), Barrandia 

 (1), Bohemilla (1), Calymene (1 to 5 +), Carman (1, 5), Ceraurus (1 to 5 +), Cyphaspis 

 (5 +), Dalmanites (1 to 5), Dindymine (1 to 5), Dionide (1, 3, 5), Llarpes (1 + ), Har- 

 pides (1), Homalonotus (2 to 5), Llkenus (1 to 5+), Lichas (1, 5 + ), Ogygia (1, 5), 

 Phacops (4, 5+), Phillipsia (5), Placoparia (1, 2), Proetus (1, 5+), Bemopleiirides 

 (5), Sphcerexochus (5 +), Telephus (4, 5), Trinucleus (1 to 5), Triopus (2). 



In Asia, Silurian beds of the Tibetan Himalayas, described by Salter and Blanford, 

 have a thickness of 6000', and afford species of Heliolites, Ptilodictya; Lept(e7ia, Stro- 

 phomena, Orthis, Ctenodonta; Holopaa, Cyclonema, Trochonema, Baphistoma, Pleuro- 

 tomaria, Murchisonia, Bellerophon, Theca; Orthoceras, Cyrtoceras, Lituites ; Calymene, 

 Sphcerexochus, Lichas, Ceraurus, Illcenus, Asaphus, but no American or European species. 



