Scottish geographical magazine . 32 SCOTTISH GEOGRAPHICAL MAGAZINE. by Schardt, Lugeon and others, in the case of the Alps, will ultimatelythrow light on the structure of the Eastern Highlands. Special reference is made in the last chapter of the first volume tothe group of rocks, comprising jaspers, cherts, pillow lavas, greenschists, grits and shales, immediately to the north of the fault at theHighland border, which have been correlated by the Geological Surveywith the Arenig cherts and lavas, and overlying unconformable sedi-ments in the south of Scotland. This correlation was natural at t
Scottish geographical magazine . 32 SCOTTISH GEOGRAPHICAL MAGAZINE. by Schardt, Lugeon and others, in the case of the Alps, will ultimatelythrow light on the structure of the Eastern Highlands. Special reference is made in the last chapter of the first volume tothe group of rocks, comprising jaspers, cherts, pillow lavas, greenschists, grits and shales, immediately to the north of the fault at theHighland border, which have been correlated by the Geological Surveywith the Arenig cherts and lavas, and overlying unconformable sedi-ments in the south of Scotland. This correlation was natural at thetime on account of the important discovery of radiolaria in the cherts, theresemblance of the Highland border rocks where not much deformed tocorresponding types in the south of Scotland, and the unconformabilitybetween the Margie group and the cherts and green schists below. But. Fig. 2.—Old Red Sandstone with Pot-holes, on the River Ericht near Blairgowrie. the progress of research beyond Scotland has rendered this conclusiondoubtful. For it has been conclusively proved that, in Anglesey, jaspersand pillow lavas enter into and form component members of a comi^lexof crystalline schists, the whole being covered unconformably byfossiliferous sediments of Arenig age, the latter containing fragmentsof the older jaspers and green schists. Moreover, the radiolaria foundin the cherts of the Highland border do not by themselves prove theserocks to be Arenig, for radiolaria have been figured and described fromthe pre-Cambrian cherts of Brittany. In the second volume the author describes the Old Red Sandstone asdeveloped in Strathmore, which includes strata belonging to the lowerand upper divisions of the system, separated by a marked unconform-ability. He clearly indicates the existence in the lower division of two THE GEOLOGY AND SCENERY OF THE GRAMPIANS : A REVIEW.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectgeography, bookyear18
