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灏忥伎璇磘…x…t锛垮ぉ/鍫�
in one of his last professional acts before his death in 1955； albert einstein wrote a shortbut glowing foreword to a book by a geologist named charles hapgood entitled earth鈥檚shifting crust： a key to some basic problems of earth science。 hapgood鈥檚 book was asteady demolition of the idea that continents were in motion。 in a tone that all but invited thereader to join him in a tolerant chuckle； hapgood observed that a few gullible souls hadnoticed 鈥渁n apparent correspondence in shape between certain continents。鈥潯t would appear；he went on； 鈥渢hat south america might be fitted together with africa； and so on。 。 。 。 it is evenclaimed that rock formations on opposite sides of the atlantic match。鈥�
mr。 hapgood briskly dismissed any such notions； noting that the geologists k。 e。 casterand j。 c。 mendes had done extensive fieldwork on both sides of the atlantic and hadestablished beyond question that no such similarities existed。 goodness knows what outcropsmessrs。 caster and mendes had looked at； beacuse in fact many of the rock formations onboth sides of the atlanticare the same鈥攏ot just very similar but the same。
this was not an idea that flew with mr。 hapgood； or many other geologists of his day。 thetheory hapgood alluded to was one first propounded in 1908 by an amateur americangeologist named frank bursley taylor。 taylor came from a wealthy family and had both themeans and freedom from academic constraints to pursue unconventional lines of inquiry。 hewas one of those struck by the similarity in shape between the facing coastlines of africa andsouth america； and from this observation he developed the idea that the continents had onceslid around。 he suggested鈥攑resciently as it turned out鈥攖hat the crunching together ofcontinents could have thrust up the world鈥檚 mountain chains。 he failed； however； to producemuch in the way of evidence； and the theory was considered too crackpot to merit seriousattention。
in germany； however； taylor鈥檚 idea was picked up； and effectively appropriated； by atheorist named alfred wegener； a meteorologist at the university of marburg。 wegenerinvestigated the many plant and fossil anomalies that did not fit fortably into the standardmodel of earth history and realized that very little of it made sense if conventionallyinterpreted。 animal fossils repeatedly turned up on opposite sides of oceans that were clearlytoo wide to swim。 how； he wondered； did marsupials travel from south america to australia？
how did identical snails turn up in scandinavia and new england？ and how； e to that；did one account for coal seams and other semi…tropical remnants in frigid spots likespitsbergen； four hundred miles north of norway； if they had not somehow migrated therefrom warmer climes？
wegener developed the theory that the world鈥檚 continents had once e together in asingle landmass he called pangaea； where flora and fauna had been able to mingle； before thecontinents had split apart and floated off to their present positions。 all this he put together in abook called die entstehung der kontinente und ozeane； or the origin of continents and oceans； which was published in german in 1912 and鈥攄espite the outbreak of the firstworld war in the meantime鈥攊n english three years later。
because of the war； wegener鈥檚 theory didn鈥檛 attract much notice at first； but by 1920； whenhe produced a revised and expanded edition； it quickly became a subject of discussion。
everyone agreed that continents moved鈥攂ut up and down； not sideways。 the process ofvertical movement； known as isostasy； was a foundation of geological beliefs for generations；though no one had any good theories as to how or why it happened。 one idea； which remainedin textbooks well into my own school days； was the baked apple theory propounded by theaustrian eduard suess just before the turn of the century。 this suggested that as the moltenearth had cooled； it had bee wrinkled in the manner of a baked apple； creating oceanbasins and mountain ranges。 never mind that james hutton had shown long before that anysuch static arrangement would eventually result in a featureless spheroid as erosion leveledthe bumps and filled in the divots。 there was also the problem； demonstrated by rutherfordand soddy early in the century； that earthly elements hold huge reserves of heat鈥攎uch toomuch to allow for the sort of cooling and shrinking suess suggested。 and anyway； if suess鈥檚theory was correct then mountains should be evenly distributed across the face of the earth；which patently they were not； and of more or less the same ages； yet by the early 1900s it wasalready evident that some ranges； like the urals and appalachians； were hundreds of millionsof years older than others； like the alps and rockies。 clearly the time was ripe for a newtheory。 unfortunately； alfred wegener was not the man that geologists wished to provide it。
for a start； his radical notions questioned the foundations of their discipline； seldom aneffective way to generate warmth in an audience。 such a challenge would have been painfulenough ing from a geologist； but wegener had no background in geology。 he was ameteorologist； for goodness sake。 a weatherman鈥攁 german weatherman。 these were notremediable deficiencies。
and so geologists took every pain they could think of to dismiss his evidence and belittlehis suggestions。 to get around the problems of fossil distributions； they posited ancient 鈥渓andbridges鈥潯herever they were needed。 when an ancient horse named hipparion was found tohave lived in france and florida at the same time； a land bridge was drawn across theatlantic。 when it was realized that ancient tapirs had existed simultaneously in southamerica and southeast asia a land bridge was drawn there； too。 soon maps of prehistoricseas were almost solid with hypothesized land bridges鈥攆rom north america to europe； frombrazil to africa； from southeast asia to australia； from australia to antarctica。 theseconnective tendrils had not only conveniently appeared whenever it was necessary to move aliving organism from one landmass to another； but then obligingly vanished without leaving atrace of their former existence。 none of this； of course； was supported by so much as a grainof actual evidence鈥攏othing so wrong could be鈥攜et it was geological orthodoxy for the nexthalf century。
even land bridges couldn鈥檛 explain some things。 one species of trilobite that was wellknown in europe was also found to have lived on newfoundland鈥攂ut only on one side。 noone could persuasively explain how it had managed to cross two thousand miles of hostileocean but then failed to find its way around the corner of a 200…mile…wide island。 even moreawkwardly anomalous was another species of trilobite found in europe and the pacificnorthwest but nowhere in between； which would have required not so much a land bridge as aflyover。 yet as late as 1964 when the encyclopaedia britannica discussed the rival theories； itwas wegener鈥檚 that was held to be full of 鈥渘umerous grave theoretical difficulties。鈥�
to be sure； wegener made mistakes。 he asserted that greenland is drifting west by about amile a year； which is clearly nonsense。 （it鈥檚 more l