On the other hand, in all parts of the world the piles of sedimentary strata are of wonderful thickness. In the Cordillera, I estimated one mass of conglomerate at ten thousand feet; and although conglomerates have probably been accumulated at a quicker rate than finer sediments, yet from being formed of worn and rounded pebbles, each of which bears the stamp of time, they are good to show how slowly the mass must have been heaped together.

Professor Ramsay has given me the maximum thickness, from actual measurement in most cases, of the successive formations in DIFFERENT parts of Great Britain; and this is the result: Feet Palaeozoic strata (not including igneous beds)..57,154 Secondary strata� � � � � � � � � � ..13,190 Tertiary strata� � � � � � � � � � � .2,240

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