A human skull fragment turned up in an archaeological survey trench dug into a parking lot near Ward Avenue last weekend, marking the sixth time human remains have been found in the path of the $5.26 billion Honolulu rail project.

The most recent find on Sunday was in a trench in the parking lot of a Ross Dress for Less store, and is believed to be a skull fragment from a young adult, according to Hinalei-moana Wong-Kalu, chairwoman of the Oahu Island Burial Council.

The city so far has discovered the remains of six people at five sites, including one set found in Kakaako in a "flexed" or fetal position that may indicate a pre-contact burial.

The State Historic Preservation Division is responsible for determining how each discovery of remains will be handled. Native Hawaiians who are involved in the burial council have asked the city to leave all remains in place, and to adjust the design of the 20-mile rail line to avoid them.

The survey work emerged as a critical component of the rail project after the Hawaii Supreme Court ruled on Aug. 24 that the city should have completed the archaeological survey along the entire rail route before beginning construction.

That decision stopped all construction, and prompted the city to dramatically step up the pace of the survey work.

The city has estimated that each month of construction delays costs $7 million to $10 million.

The city has excavated more than 350 trenches as part of the survey, and has about 35 more trenches to go to complete the work, according to records provided by the Honolulu Authority for Rapid Transportation.

The trenching should be finished by the end of the year, and the city hopes to restart construction on the rail project early next year.