(Brian Maffly | The Salt Lake Tribune) Josh Ewing, executive director of Friends of Cedar Mesa, inspects the base of an 800-year-old tower that once stood over an Ancestral Puebloan settlement on Alkali Ridge east of Blanding. The Bureau of Land Management has issued numerous new oil and gas leases in the area, which is blanketed with artifacts — over the objections of historic preservation groups that fear the BLM lacks sufficient information about thousands of cultural sites to ensure their protection.