YELLOWSTONE NATIONAL PARK (AP) - A federal agency has asked park Superintendent Suzanne Lewis why a cell phone tower was apparently built differently than what was originally planned.

The initial design for the tower in the Old Faithful area was deemed acceptable by experts at the Wyoming State Historic Preservation Office.

But earlier this year, the office complained that the 100-foot, silver tower is inconsistent with the proposed design and the area's 100-year-old Old Faithful Lodge and other historic structures.

Alan Stanfill, a senior program analyst for the Advisory Council on Historic Preservation, said the council hopes to gather more information about the tower from the National Park Service.

"At this point, we're trying to determine what the facts of the matter are and whether there's an adverse effect," he said Tuesday.

The original plan called for a tower no taller than 10 feet above treetops and painted to match nearby burned trees. State officials looked at the tower last summer and said it was incompatible and quite visible in the historic area around Old Faithful geyser.

"Its presence within the viewshed of the Old Faithful Historic District has created a very noticeable adverse effect to this district," Judy Wolf, compliance program manager for the state office, said in a letter to park officials on Jan. 7.

Park officials have said that the tower is important for emergency communications in Yellowstone, especially during the summer months.

"There have been some discussions about camouflaging the tower somehow but nothing has been decided," said Stacy Vallie, a park spokeswoman.

She said the park has not yet received the letter from the federal historic preservation council.

Western Wireless Corp. was given permission to build the tower in 2001 but it was taller than the proposed design.