Page:A Treatise on Geology, volume 1.djvu/73

 CHAP IV. {| style="font-size:85%;line-height:140%;border-style:none;text-align:left;" cellspacing="0" cellpadding="3"
 * colspan='5' style="text-align:center;" | Silurian System.
 * style='border-right:thin solid;' rowspan="5" |
 * rowspan="3" | 660
 * style='border-right:thin solid;' rowspan="3" | $$\left\{ \begin{matrix}\ \\ \ \\ \ \end{matrix} \right.$$
 * style='border-right:thin solid;' | Upper Ludlow rock.
 * Laminated sandstone.
 * style='border-right:thin solid;' | Aymestry limestone.
 * Subcrystalline limestone.
 * style='border-right:thin solid;' | Lower Ludlow rock.
 * Sand shale, with concretionary limestone.
 * rowspan="2" | 600
 * style='border-right:thin solid;' rowspan="2" | $$\left\{ \begin{matrix}\ \ \\ \ \end{matrix} \right.$$
 * style='border-right:thin solid;' | Wenlock limestone.
 * Grey and blue subcrystalline limestonne.
 * style='border-right:thin solid;' | Wenlock shale.
 * Shale and earthy limestone.
 * style='border-right:thin solid;' rowspan="4" |
 * rowspan="2" | 830
 * style='border-right:thin solid;' rowspan="2" | $$\left\{ \begin{matrix}\ \\ \ \\ \ \end{matrix} \right.$$
 * style='border-right:thin solid;' | Limestones and sandstones.
 * Laminated limestones and sandstones.
 * style='border-right:thin solid;' | Conglomerates, &c.
 * Gritstones, conglomerates, limestones.
 * rowspan="2" | 400
 * style='border-right:thin solid;' rowspan="2" | $$\left\{ \begin{matrix}\ \\ \ \\ \ \end{matrix} \right.$$
 * style='border-right:thin solid;' |
 * Dark calacareous flags, sandstones, &c.
 * style='border-right:thin solid;' |
 * }
 * style='border-right:thin solid;' | Conglomerates, &c.
 * Gritstones, conglomerates, limestones.
 * rowspan="2" | 400
 * style='border-right:thin solid;' rowspan="2" | $$\left\{ \begin{matrix}\ \\ \ \\ \ \end{matrix} \right.$$
 * style='border-right:thin solid;' |
 * Dark calacareous flags, sandstones, &c.
 * style='border-right:thin solid;' |
 * }
 * style='border-right:thin solid;' |
 * }
 * }

In possession of this complete section of all the principal masses of stratified rocks in the British isles, and guided by a map of the ranges of each of these on the surface,—aware, also, that within the narrow compass of these islands some of the groups of strata vary extremely (as the lower oolites, which are principally calcareous near Bath, but principally arenaceous near Whitby), and others have only a limited range (as the magnesian limestones), we may proceed to inquire how far the sections of other natural districts agree with that given above.

Throughout the great basins of Europe, and parts of Asia and Africa, including the countries bordering on the German Ocean, the Baltic, the Black Sea, and the Mediterranean, within the mountain boundaries of the Ural, Caucasus, Greece, Calabria, the Atlas, Western Spain, Brittany, Cornwall, the west of Ireland, Scotland, and Scandinavia, the general features and succession