A lost city of the Maya Indians, which existed from prehistoric times until after the Spanish conquest of Yucatan, is being excavated in a thorny wilderness area by the National Geographic Society and Tulane University.

The city is Dzibilchaltun, a metropolis from which the Mayas vanished after becoming the most civilized peoples of pre-Columbian America.

Dzibilchaltun’s gray ruins cover an area of 20 square miles north of the Yucatan capital, Merida. The excavation project in Mexico is headed by Dr. E. Wyllys Andrews, an archeologist affiliated with Tulane’s Middle American Research Institute. Luis Marden of the Geographical Society’s foreign editorial staff, leads an underwater team that is exploring a huge cenote, or natural well, in the center of the city.

Largest in New World

The city apparently became the largest in the New World after its founding between 2000 and 1000 B. C., Dr. Andrews reports in the January issue of the magazine. He says it kept growing and thriving uninterruptedly through the crises of Mayan history and into Spanish colonial times.

In its heydey, Dzibilchaltun bristled with pyramidal temples, palaces and buildings of vaulted stone. The city’s size is significant because most Mayan cities formerly were thought to be only ceremonial centers.

Until now, the lost city has been overshadowed by other well-known Mayan centers, such as Chichen Itza and Uxmal. Among the city’s most striking features are a great white causeway paved with limestone and a rambling complex of buildings called the Palace. This covers a dozen acres and could hold most of the principal buildings at Chichen Itza.