St. Mary's County has a phantom -- a green, snout-nosed toad that bleats like a sheep.

State naturalists say the creature lives in the county's marshy southernmost reaches, though few can remember actually seeing one.

Now, the Maryland Department of Natural Resources says the elusive toad, endangered in Maryland but common in many southern states, probably lives on a 24-acre tract that the Southern Maryland county wants for a new elementary school.

County officials just don't believe it.

"It's a rural area," said county Commissioner Larry Jarboe (R-Golden Beach). "They might be hearing sheep."

The county and the DNR reached a compromise last month: The school can be built on the site off Indian Bridge Road -- as long as construction follows toad-friendly guidelines. The state has given the county the 24-acre parcel in St. Mary's River State Park in return for 21 acres of county land near the state park and 18 acres within the St. Mary's River watershed.

The toad's mating habits will dictate much of the construction work, requiring minimal blacktop and a strict time frame for construction.

"We want to have a time period on it because of the toad's . . . breeding seasons," said Michael E. Slattery, the DNR's assistant secretary of forests, parks, fish and wildlife.

This isn't the first time the rural county's development plans have run headlong into the toad. In the mid-1990s, the amphibian held up work on Indian Bridge Road -- "toad road," a local official called it -- until a series of traffic fatalities prompted lawmakers to take action.

"People were just sick and tired of people dying [on the road] as a result of a toad that nominal people had seen," Jarboe said.

The road was finally finished after state Sen. Roy P. Dyson (D-St. Mary's) pushed through legislation to exempt the road from toad protection.

Frogs and toads run rampant over the quiet community just off Indian Bridge Road, where home lots are at least an acre. Most residents say they have never heard or noticed the eastern narrow-mouthed toad.

"I have never seen one of those," said Diane Conley, 43, who lives in a development near the site and whose fourth-grader must travel 15 to 20 miles round trip to Piney Point Elementary School. "If this frog is so prevalent . . . it can move south."

Slattery said only experts -- such as hobbyist ecologists or those with herpetologic expertise -- can detect a toad so reclusive as the eastern narrow-mouth. The toad, the size of a half-dollar with a pointy snout, burrows underground in a state of estivation, or dormancy, for much of the year.

"They are very inconspicuous," he said, "and their life history habits don't have them out in the open where people can see them often."

State naturalists have recorded about a dozen sightings of the toad in St. Mary's County in the past 10 years, said Paul Peditto, director of the DNR's Wildlife and Heritage Service.

County Commissioners President Thomas F. McKay (R) and Jarboe said they have never received documentation of the sightings. That information, Peditto said, is not released by the department.

"We don't do those types of individual counts," he said. Otherwise, people might hunt out endangered species, such as the bald eagle, and put them at risk, he said.

But development couldn't be worse for the toad than farming, one neighbor said.

"They've been farming the land for years," said Kelly Bowling, a resident of the subdivision across the street from the school site. "If that didn't kill the toad, a school won't."

Still, the school will proceed only under an advisory board of DNR representatives.

"A layperson would say that [field] is not fantastic toad habitat," Slattery said. "The issue is more the concern that the impervious surfaces and changes to the hydrological regime would have an impact on more suitable habitats nearby. We want to make sure [there's] a limited disturbance."

With nearly 450 students in temporary trailers across the fast-growing county and more than 1,000 students expected to use them in five years, school officials chose the school site last fall and brought Dyson and county commissioners into the effort. The site lies between two growth areas -- Lexington Park and Leonardtown.

"Geographically, it was in the location that would help relieve overcrowding in four other elementary schools without major redistricting," said J. Bradley Clements, chief administrative officer for the county school system.

The field -- now covered in cornstalks -- has been leased to farmers for years, making it easy to clear for an elementary school.

School officials said students at the new elementary, slated to open in 2008, will be taught about the endangered toad and environmental preservation.

They might even consider making the toad the school's mascot, Jarboe said, though no one seems to have seen it.

"When you have something such as this species that is rarely seen and has odd habits," Slattery said, "it takes on an almost mythical tone."

J. Bradley Clements of the St. Mary's County schools stands on the site where endangered amphibians are found.The eastern narrow-mouthed toad is the size of a half-dollar and bleats.