265

geology of England.

that county as in Dorsetshire and Somerset­ shire . Having arrived at regular argillaceouscoal strata, how much deeper we must sink togain the first bed of workable coal, could onlybe ascertained by trial: it probably would notexceed forty or fifty yards. I am, however,inclined to believe that the lower secondarystrata do not extend to any considerable di-stance beyond their known limits, and thatcalcareous strata near the coast lie on primaryor transition rocks, without the interventionof coal strata. The determination of this ques-tion will be a'subject of the highest nationalimportance in the course of a very few centu-ries, when the coal fields which supply themetropolis and southern counties are workedout. Our prosperity and greatness as a ma-nufacturing nation will depend on the resultof this inquiry.

The northern extremity of the low calca-reous district is terminated by a range of loftyhills in Yorkshire , called the eastern moor-lands, marked B in the map : it is continuedbeyond them near the coast of Durham , andappears in some parts of Northumberland .

Th«