HAIKOU, May 25 -- A Chinese archaeological team has wrapped up its underwater excavation in the Xisha archipelago in the South China Sea, with scores of relics uncovered and several surveys conducted, local authorities said Monday.

The team returned to Qinglan Port, Wenchang City, Hainan Province, on Monday after a 40-day mission, according to team leader Deng Qijiang.

During the mission, a total of 37 items were retrieved from a shipwreck site near the Shanhu Island, including stone building material and shattered porcelain, although no ship was found, Deng said.

The team also carried out a survey on land at ruins on Ganquan Island, and an underwater survey on another sunken ship around Jinyin Island.

The event was co-organized by the State Administration of Cultural Heritage (SACH) and Hainan's provincial cultural heritage administration.

This is the second notable underwater archaeological excavation in the South China Sea following the Huaguang reef number one shipwreck in 2008 in the Xisha Islands, where a vessel loaded with porcelain sank more than 700 years ago, according to Chai Xiaoming, an SACH official.

"Underwater surveys help us better understand China's overseas trade through history," Chai said.

China has intensified efforts on underwater archaeology in recent years. As of last year, China had discovered more than 120 shipwrecks around Xisha, Nansha and Zhongsha islands.