The Piltdown Man Hoax, the most spectacular scientific fraud of the 20th century, was cooked up in part by the well-known French Jesuit Pierre Teilhard de Chardin, a Harvard historian of science has concluded.

Writing in the August issue of National History, magazine published by New York's American Museum of National History, Dr. Stephen Jay Gould lays out a solid though circumstantial case that Teilhard was an active and willing accomplice of Charles Dawson, the British naturalist who has long been accused as the lone culprit in the hoax.

"I have found a pattern that seems hard to reconcile with his [Teilhard's] innocence," Gould writes after more than a year of scientific detective work in unearthing the French priest's role in the hoax. "My case is, to be sure, circumstantial, but I believe that the burden of proof must now rest with those who would hold Father Teilhard blameless."

The hoax began in 1912 when a skull was unearthed from a gravel pit at the village of Piltdown, near Hastings on the southeast coast of England. Reconstructed from fragments found buried side by side, the skull seemed to consist of the cranium of a man and the jaw of an ape-like creature whose teeth appeared both ancient and human.

The "discovery" was followed almost immediately by an almost identical find in another gravel pit, identical find in another gravel pit, indicating that this was a real creature and not just a chance collection of bones.

Believed to be as much as a million years old, Piltdown Man became an overnight sensation. It was hailed as a "missing link" in man's ancestry, older than both Neanderthal and CroMagnon man.

Both Piltdown fossils were unearthed by Dawson, assisted in his digs by the young Teilhard, just ordained and then studying poleontology. Smith Woodward, curator of the British Museum, visited the digs on occasion but served mainly as the man who verified the discoveries.

Though not without doubters, the hoax remained intact from 1912 to 1952, when three British scientists proved not only that the Piltdown Man's teeth had been artificially filed and stained to suggest age but that ancient animal bones from faraway lands had been placed in the gravel pits to hint more strongly of age. Radioactive dating proved also that the cranium came from the skull of a modern man.

For the last 28 years, Teilhard was held blameless in the fraud because of his inexperience. At 31 and a fledgling naturalist at the time, he was said to have duped by Dawson. So, too, was Woodward, who was described as "too dedicated and too gullible" to see through the fraud. Dawson alone was blamed by the world's scientists as the culpit.

The first part of Gould's case against Teilhard consists of the elephant and hippo bones found in the Piltdown pits. The bones were found to have come from Malta and Tunisia, where Teilhard collected specimens on trips between Egypt and France in the years 1905 and 1908.

The second part of the case is stronger, involving an exchange of letters between Teilhard and Kenneth Oakley, one of the three-British scientist who uncovered the hoax 40 years later. Gould carefully reconstructs what happened at the digs and says that Teilhard lied to cover up what he could no longer remember.

In what Gould calls Teilhard's "fatal error," Teilhard said that on his first visit to the second site Dawson showed him where he'd found the second Piltdown skull.

"This cannot be," Gould writes. "Dawson 'discovered' the skull bones at Piltdown 2 in January, 1915 and the tooth in July, 1915. Teilhard was mustered into the French Army in December, 1914 and was shipped to the front, where he remained until the war ended. He could not have seen the remains of Piltdown 2 with Dawson, unless they manufactured them together before he left and before Dawson died in 1916."

Teilhard's slips go on, writes Gould. He told Oakley he visited the second site in 1913 but forgot whether the skull had been found or not. In another letter, he wrote that he could no longer remember when he visited the site. How, Gould suggests, could Teilhard have forgotten what he had called "one of my brightest and earliest paleontological memories."

Gould strengthens his case by following the career of Teilhard. He became a brilliant naturalist and philosopher, wrote 23 books and at his death in 1955 was a cult figure. His "Phenomenon of Man" is a worldwide best seller. He mentioned his role in Piltdown only six times in all his work, then only as footnotes. Gould suggests Teilhard was so embarrassed he could not bring himself to mention it.

Why did Teilhard do it? Gould suggests Dawson and Teilhard did it as a joke, then watched helplessly as the joke got out of hand. Gould also suggests Teilhard did it because of his religious belief in the evolution of the human spirit.

"Teilhard believed that evolution moved in an intrinsic direction representing the increasing domination of spirit over matter," Gould writes. "Piltdown provided proof, the only available proof" that this had happened early on in time.