Anthropologists have unearthed what they believe is the world's oldest known religious shrine, pushing back the date for formal religious ceremonies-- including use of an altar and a stone idol--into the Old Stone Age.

The altar and stone face, dated at about 14,000 years ago, were found in a small cave sanctuary near Santander, Spain. Until now, the oldest known elaborated shrines were those in the Middle East dating from 9,000 years ago.

Evidence of religious beliefs can be found as far back as 50,000 years ago, but until now, no one has found a full-fledged Stone Age shrine.

The most striking aspect of the shrine is its detail, suggesting rituals and symbols "just as complex and intricate as those in the religions of today," said Dr. Leslie G. Freeman, one of the shrine's four discoverers.

The complex detail of the shrine, including the stone face, is considered unlike anything found in other Stone Age digs. The stone face, carved and painted, depicts a creature that is half human and half lion, according to Freeman, a professor at the University of Chicago. Half of the face shows an apparently smiling, bearded man, and the other half shows a whiskered cat with a projecting fang.

Freeman said the face indicates a sophisticated sense of opposites and their resolution, just as in modern religions. "Just as we today sometimes talk about man as a beast that needs to be controlled, these people seemed to be showing us that same sense," Freeman said.

Freeman and Dr. Richard Klein, also of the University of Chicago, discovered the shrine with Dr. Ignacio Barandiaran of the University of Santander and Dr. J. Gonzalez Echegaray of the Altamira Museum in Santillana, Spain.

The discovery was at an archeological site called El Juyo cave, which had been found and worked to a limited extent years ago. The current expedition went back to dig deeper and study more carefully various levels in the cave floor.

In one level of dirt, the researchers found the stone face, in an extraordinarily preserved state and standing on a two-and-a-half-foot mound. A six-by-four-foot altar slab still stood in place on an adjacent mound. The mounds were built up with alternate layers of geometrical designs, worked in clay, and symbolic animal bones and spear points.

In three pits arranged in conjunction with the mounds, shells and bone needles for sewing were found. Freeman said that the separation of the weapons from the sewing implements suggests that male and female roles in the culture were reflected in the religious rites.

The stone face that presided over the scene is about 14 inches high and 13 inches wide. A natural vertical crack in the stone was used to divide the face into its animal and human parts. Extensive cutting with stone tools marked out the teeth, beard, mustache, eyebrow and hair of the man depicted. Similar detail was found on the lion's face.