BOOK REVIEW : Sands of Science Force Shift in Theories : THE OTHER SIDE OF THE MEDAL; A Paleobiologist Reflects on the Art and Serendipity of Science <i> by Everett C. Olson</i> McDonald & Woodward $19.95, 182 pages

Mavericks start scientific revolutions. Normal scientists carry them through, carefully fitting scrupulously gathered data to the new paradigm. They explain the familiar in ways that make people wonder how earlier folk, for example, could ever have thought the world was flat or the sun the center of the universe.

What is so wonderful about Everett C. Olson’s reflections on his life as a paleobiologist is his candor as a normal scientist.

In “The Other Side of the Medal,” he recalls his reluctance in the 1960s to accept the new geology of plate tectonics.

The notion that continents are “restless drifting islands carried on rigid plates that made up the outer part of the earth” disturbed him, “for it shook the whole basis of geological theory.” Yet plate tectonics would explain puzzles in his own field, the evolution of animal life.

While at the University of Chicago in the 1930s, Olson fell heir to a collection of fossil Therapsida from the Permian strata in Africa, advanced mammal-like amphibians that are an evolutionary bridge between sea and land creatures.

These fossils sparked a lifetime interest in the Permian period, some 260 million to 200 million years ago, whose fossils have been discovered on several continents.

Olson explains that the word Permian comes from Perm, a city 700 miles east of Moscow, where in 1780 copper miners discovered fossils in a particular rock stratum. During the early Permian, he explains, most animal life was in the sea. But as the early Permian merged into the later or Upper Permian, and on to the Triassic, land-based life began to flourish.

At some time in between, the greatest number of animals in the history of life disappeared, leaving only two lines of land creatures--the group of snakes, lizards and now-extinct dinosaurs, and our ancestral mammals.

Olson spent the 1930s digging in the Permian hills of West Texas. After World War II, he realized that if he were to relate the African fossils and those from the Soviet Union to the Permian in North America, he would have to find American fossils in higher, more recent strata. He selected new sites in Texas and Oklahoma where he discovered fossils even closer to the Soviet samples than he’d expected.

Determined to examine the Soviet collections personally, he applied for a visa. Despite Cold War obstacles--there had been no Soviets at international geological meetings since 1937--he arrived in Moscow in 1959 for the first of seven visits.

But even the uncanny similarity between the fossils unearthed at distant burial sites did not convince Olson that plate tectonics offered an explanation. It would be another decade before Olson fully accepted the reality of a single ancient land-mass--Pangea--on which the extinct animals lived and from which the present continents broke away.

By the mid-1970s, another of the scientific theories with which Olson had grown comfortable was showing signs of wear. In 1959, centenary celebrations of Darwin’s “Origin of Species” hailed Neodarwinism, the marriage of evolutionary theory and Mendelian genetics. But Neodarwinism came under siege as evolutionists like Steven Gould questioned the assumption that evolution proceeded at a steady rate. Maybe it moved in punctuated leaps? Maybe external cataclysms, like gigantic meteors, were responsible for radical die-offs like the one at the end of the Permian?

In “The Other Side of the Medal” we get to meet an especially American scientist, stubborn but open-minded, a field worker who was at home with cowboys as well as academicians.

Olson kept his sights on the forest as well as the trees, as demonstrated by his collaboration with statistician Robert A. Miller in developing the concept of “chronofauna,” the study of the changes of an entire fauna moving through time, not just the development of an individual animal, that has become a standard ecological approach.

Now a professor emeritus at UCLA, Olson continues to tease out the riddle of evolution at CSEOL, UCLA’s Center for the Study of Evolution and the Origin of Life, where he considers the ideas of astronomers, geologists, biologists as well as writers of science fiction.

Next: Jonathan Kirsch reviews “Movie Anecdotes” by Peter Hay (Oxford University Press).