BOOK REVIEW / Life on the Oregon trail: Go to it, Snooks]: The plains across John D Unruh Pimlico, pounds 9

THE SUBJECT of John D Unruh's fine and sober book is one of those great historical episodes from which bright, sweet myths have been spun like candy-floss, but about which we know almost nothing. The long and hazardous migration of 300,000 settlers, who for two decades walked half way across America in search of a better life in Oregon and California . . . this is the story that gripped America for real in the middle of the 19th century, only to grip it again, in a thousand celluloid reincarnations, 100 years later.

Indeed, history has been forced into hiding by the big guns of cinema. Heaven only knows how many hard-driving, God-fearing migrants were attacked by Indians in Hollywood's re-creation of America's long, pioneering march. Heaven only knows how many thousands of Indians fell, in film after film, to the accurate shooting of nice-looking young guys in sharp neckerchiefs.

The figures divulged by Unruh tell a rather different story. In the 1840s, the first decade of the wagon trains, just 67 travellers were killed by Indians. Twice as many Indians were shot by travellers, and anyway, half of the casualties were in 1849 - the year of the Gold Rush, the year that drove trigger-happy fortune- seekers across the plains, the year that marked, for the American Indian, the beginning of the end.

Thirty-four people killed over nine years isn't nothing. It is enough to scotch, at any rate, the contrary idea that the Indians were berry-eating peaceniks who wouldn't have hurt a fly. But it is also the death toll, these days, for a busy fortnight in Washington. Moreover, it was the aggressive and suspicious behaviour of the migrants themselves that turned mere braves into hostiles. It really is extraordinary that so vibrant and enduring a myth as Cowboys and Indians should have flowered from so slender a root.

From 1840 to 1845, however, while the newspapers warned constantly of the Indian threat, not one white American was killed. Yet several zealous and incorruptible travellers, approached by peaceful Indians seeking trade or gifts, started blasting away. And in 1847, Loren Hastings saw Pawnee Indians begging and attempting to steal horses, and wrote: 'The Pawnee Indians are the greatest thieves I ever saw - the best way I think to civilise or Christianise Indians is with powder and lead, & this is the way we shall do hereafter.'

Before long, President John Tyler was going on about 'the depredations and assaults of treacherous and piratical savages', and everyone was calling for troops, forts, helicopter gunships, napalm - whatever there was. Unruh shows that the Indians presented only a small danger. Cholera was the biggest killer, followed by drowning, firearm accidents and starvation. Indian 'depredations' were responsible for less than 4 per cent of the people who didn't make it to California or Oregon.

Unruh's conclusion is calm: 'That Indian begging and thievery were considerable nuisances cannot be denied, but it is also clear that the extent of the Indian attacks on overland caravans has been greatly exaggerated. In fact, there is considerable evidence that the fatal trail confrontations which did occur were usually prompted by emigrant insults and disdain for Indian rights, as well as by indiscriminate and injudicious chastisement meted out by the US Army.'

The story of the migration is, naturally, rather larger than this. Unruh has a marvellous time in the newspaper libraries, documenting the rivalry between the leading Missouri towns as they competed for the business of the travellers. At first, newspapers emphasised the dangers of the trip. They spoke of 'a howling wilderness of snow and tempests' infested with Indians 'of more than Scythian savageness'. But things quickly turned promotional, and soon editorials sang hymns of praise to the 'noble, migratory legions' and spoke of 'those flowery seas, the Prairies'.

Individual tragedies made headlines - one party trapped by snow in the Sierras resorted to cannibalism in an attempt to stave off death. But good news was also eagerly received and broadcast. In 1844, word arrived that a baby boy had been born en route, and had been given the name 'Oregon Snooks'. The editor of the New Orleans Daily Picayune recorded that this was 'a name which may hereafter be destined to fill the trump of fame, and ring through the Rocky Mountains to the dismay of grizzly bears. Go to it, Snooks.'

Snooks was lucky: Oregon was by some way the more fashionable destination. At one junction a piece of flashy golden quartz stood on one path, a sign saying 'Oregon' on the other. California was for gold-diggers, it implied, but Oregon was for people who could read.

One of the ironies of the march was that the easiest pickings were to be had not in the distant gold fields but in the trading posts. Unruh exhaustively charts the various prices for flour, bacon, sugar, coffee, guns and liquor, and quotes one frustrated traveller who found the traders 'as keen as the shrewdest Yankee that ever peddled clocks or wooden nutmegs'. Another concluded bitterly: 'While others are chasing wealth, they are catching it.'

This burst of entrepreneurial vigour is perhaps the most telling episode in the book. For the great march west is one of America's most cherished myths. It shows a nation of pioneering seekers and dreamers, forging towards the sunset in search of a better life. Unruh supplies a more realistic version: the pioneer spirit looks, in his account, like a sham, a mixture of pious and sometimes bad-tempered opportunism: greedy, brave, selfish, stubborn and inclined to violence. These days we know that you can't trust a cowboy, not even if he's called Oregon Snooks. The Plains Across proves, in the calmest possible fashion, that you never could.