A gently nurtured English girl and three friends discover for themselves that treasure hunting and commerce in the jungles of British Guiana and Venezuela are not all exciting adventure and local color and a fortune round the corner. But they have plenty of everything -- and more than they bargained for -- in the discovery. Ship and plane and train -- before the treasure hunt began -- gave the travelers an unusual picture of the islands and the coast towns and the Andean highlands. The jungle adventures are good reading, with their share of humor and enthusiasm in the telling. Sell as travel-adventure.