CONTENTS. 
xviii 
between the Azoic and Protozoic Rocks.-Silurian strata in the government of St. Petersbnrgh 
represent the Lower Group only .-Transverse sections of the same to the South of St. Peters- 
burgh and on the rivers Ishora, Tosna, Volkof and Siass, showing that the Lower Sdur.au Rocks 
are there at once surmounted by strata of Devonian age.-Silurian Dislocations and Flexures 
accounted for.— The Lower Silurian beds of Esthonia and Kovno pass upwards into Limestones 
with Pentameri, intermediate between the Lower and Upper Groups.-Upper Silurian Rocks 
developed in the Isles of Dago and Oesel.-Review of the characteristic Silurian Organic Re- 
mains, proving a division into Lower and Upper Zones in Russia, as in Norway and Sweden. 
(See Map, Table and Section, Plate VI.) 
CHAPTER IV. 
DEVONIAN, OR OLD RED SYSTEM. 
Great extension of the System.— Described in ascending order, from the junction of its lower strata 
with the Silurian rocks of the Volkof, to the contact of its upper beds with the Carboniferous 
Limestone in the Valdai Hills.-Range to Vitegra, Andoma, and Archangel.-Range and con- 
tents in Courland, Livonia, &c.— Great South-eastern band extending to the Governments o 
Orel and Voroneje, and sections of it on the rivers Oka and Don (see Section beneath 
the Map, Plate VI.)—Organic Remains of the System in Russia compared with those of 
Western Europe 
CHAPTER V. 
CARBONIFEROUS SYSTEM. 
Carboniferous System of Northern and Central Russia the equivalent of the Mountain Limestone of 
Great Britain. Divided into three Fossiliferous Zones. — Lower Zone with seams of Coal in 
Sand and Shale described in the Valdai Hills. — Extension of Limestone to Vitegra. White 
Limestone of Archangel. — Great Central Basin of Carboniferous Limestone (see Section be- 
neath the Map, Plate VI.).— Lower Southern edge of, near Kaluga, Tula, &c. White Lime- 
stone of Moscow.— Extension of this central mass along the river Oka to Kasimof and 
Jelatma. Upper or Fusulina Limestone at Kovrof and near Samara on the Lower Volga .... 
CHAPTER VI. 
CARBONIFEROUS REGION BETWEEN THE DNIEPER AND THE DON. 
Introduction.— Extent and general Relations of the Tract.— Crystalline Rocks of the Southern 
Steppes.— Carboniferous Rocks described in an ascending order on the nver Kalmiuss. The 
same Section prolonged to the Upper Carboniferous strata North of Gorodofka.-Sections on 
the river Miuss and Krinka.-The Bituminous Coals of the Western and Northern Districts 
shown to be of the same age as the Anthracite on the South-west.— Anthracite of Popofskoe, 
and its value.— Sections on the Donetz.— Bituminous Coal-fields of the Northern Tracts.— 
