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REGIONAL SURVEYFeatures of Land and ClimateBy HUGO SJORSGeology and topographyHISTORICAL SUMMARY .-Sweden belongs to Fennoscandia,a physiographical area consisting ofNorway, Sweden, Finland and northwestern Russia(Kola and Karelia) and characterized by predominantlyvery ancient bedrock, Pleistocene glacialsculpture, and Late-glacial and Post-glacial crustaluplift.The long and complicated history of Pre-Cambriangeology cannot be treated here. At the endof this era, much of Fennoscandia was worn downtheSub-Cambrian peneplane is still locally preserved-andthen successively submerged during theCambrian and Ordovician and to some extentSilurian epochs. This resulted in the deposition ofvery extensive sediments on top of the Pre-Cambrianrocks. Later, near the middle of the Palaeozoicera, western Fennoscandia rose and was foldedto form part of the Caledonian range, which alsoincludes the Scottish Highlands. In Scandinaviathese mountains, often referred to as the Scandes,were formed through a process involving greateastward overthrust of nappes that partly coveredvarious older rocks as well as some Cambro-Silurianlayers. These sediments therefore are preservedalong and beneath the Caledonian border. Othersediments were included in the Scandes themselvesoften in a high-metamorphic state.East of the Caledonian border the country alsorose but was far less disturbed, although numerousfaults occur. During hundreds of million years,Sweden was prevailingly dry land and subject toweathering and erosion which wore off the sedimentsfrom most areas, except for remnants (seebelow), and cut a series of new or regenerated peneplanesdown into the Caledonian rocks or, furthereast, the Pre-Cambrian basement, all the way fromthe summits of the Scandes to the present coast.Finally, during the Pleistocene, the entire countrywas repeatedly covered by inland ice and the bedrockevidently strongly scoured in many places.THE SCANDES.-Fennoscandia's western part, theCaledonian mountain range or the Scandes, has arugged but usually not very bold topography. TheScandes are much like the Scottish Highlands buttwice as high. The rocks of the Scandes are largelyhard-schistose and prevailingly silicious, but theyalso include softer, frequently somewhat calcareousrocks, as part of the phyllites. In consequence,quite large areas in the Scandes harbour a basicolousflora, or rather a vegetation containingvarious basicoles, although limestone, dolomite,and ultra-basic rocks such as soapstone, peridotiteand serpentine are all very local in the Scandes.Rocks of intermediate standard are some micaschists,certain eruptives, and the hard amphibolitesthat form many of the high summits.However, the majority of soils in the Scandes arerather poor, considered as substrata for plant life.Still the general standard is far better than is usualin the eastern and southern, Pre-Cambrian parts ofFennoscandia.Extensive regions, some alpine and some wooded(forming foothills or plateaux to the east), are builtup of quartzites, sparagmites, granites, syenites,porphyries, etc., that are very low in calcium andmagnesium and high in silica. In these areas, thealpine vegetation is poorer than normal in speciesbut yet often more variable and even richer thanthat of adjoining high-level woodlands. Most ofthe latter areas, such as for instance the sparag-Acta Phytogeog.r. Suec. 50