. Plant succession; an analysis of the development of vegetation. Plant ecology. 306 PAST CLIMATES AND CLIMAXES. ^â ^V. A Sea level a" *^ ','.â â >-, X r^ =S5r / , ' 4? » ^ ^ *«:,* 'aT^'^"'^*^ X ^ V \ N -; V â iS. ^SiSS^ N ' \ ⢠> V s - ^ t^ '^^^^^^???: ^ beds or formations separated by a time interval, while a similar section of the adjacent and lower conformity shows the time interval as recorded in a bed or formation derived from the erosion of the exposed portion of the formation upon which it rests (fig. 24). Unconformity is, then, an invaluable indicator of deformation
. Plant succession; an analysis of the development of vegetation. Plant ecology. 306 PAST CLIMATES AND CLIMAXES. ^â ^V. A Sea level a" *^ ','.â â >-, X r^ =S5r / , ' 4? » ^ ^ *«:,* 'aT^'^"'^*^ X ^ V \ N -; V â iS. ^SiSS^ N ' \ ⢠> V s - ^ t^ '^^^^^^???: ^ beds or formations separated by a time interval, while a similar section of the adjacent and lower conformity shows the time interval as recorded in a bed or formation derived from the erosion of the exposed portion of the formation upon which it rests (fig. 24). Unconformity is, then, an invaluable indicator of deformation movements. In the case of general body deformations, unconformity should be the rule. Conversely, general or widespread unconformity is evidence of great deforma- tion, and hence of a major cycle. Local unconformity indicates minor or regional deformation, though the latter may be related to the body deforma- tion or independent of it. In consequence, it is regularly associated with the regional gradations which are here regarded as typi- cal cycles of erosion. In any region the series of gen- eral and local unconformi- ties is an exact measure of the alternation of defor- mation and gradation, and hence of generally conti- nental and oceanic climates. If the latter be checked by the critical scrutiny of the fossils of the land biota found in the two uncon- formable formations, and especially by those found in the conformable forma- tion which results from the erosion phase, we secure an almost perfect record of the sequence of deformation, climate, vegetation, and fauna. Correlation of climates.â It is increasingly evident that the changes in past climates may have been caused either by deformation or by solar variations, as well as by the interaction of the two. The problems of climatic change are considered in some detail in the next section, and the general series of climatic cycles is suggested. It will here suffice to point out the correspondence of the major
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