A spokesman for the head of the National Park Service says the agency has serious concerns about a proposed resort development on the edge of Yellowstone National Park.

Developer Lewis Robinson has proposed a $28 million grizzly bear theme park near Yellowstone's west entrance, with captive grizzly bears as the principal attraction."This proposal to put a grizzly bear theme resort on the border of Yellowstone is like putting roller derby on the edge of the Sistine Chapel," George Berklacy, a spokesman for Park Service Director James Ridenour, said Thursday.

"Yes, the director has expressed serious concerns about this facility," he added.

Berklacy said "Grizzly Park" is one of several theme resorts encroaching on national parks and the director is worried the developments may compromise park values.

In a recent letter to the Gallatin County planning office, park Superintendent Bob Barbee also outlined several problems with the proposed development.

He said odors associated with the development could attract wild bears in Yellowstone. Park biologists fear captive female bears may attract wild male bears to the complex.

Barbee also noted the resort would be close to Yellowstone's employee housing and cited possible traffic congestion.

The Gallatin County Commission was scheduled to consider Robinson's proposal on Friday.