The Martha’s Vineyard Land Bank has signed a contract to purchase 41.1 acres on Chappaquiddick, including some 900 feet of shoreline on Cape Pogue Bay.

The acquisition will be added to its existing Three Ponds Reservation, bringing the total contiguous land area to 357.7 acres.

In an announcement on Monday, the land bank said the land, at the end of Jeffers Lane, would cost $4.95 million. The sellers are Judith Self Murphy, E. Baldwin Self Jr. and Karen Self Osler.

“The property hosts a wide range of uplands and water. It includes 900 feet of shoreline on Cape Pogue Bay plus four ponds, the largest of which is a three-acre pond in the heart of the land,” a statement said.

“The focal point of the property is the six-acre promontory containing a house and two outbuildings; all will be removed and the promontory will be restored to wildland.”

Most of the new land — 35.3 acres — is covered by a conservation restriction donated by the Self family 20 years ago, said land bank executive director James Lengyel.

Four separate previous transactions had given the land bank about 1,100 feet of shoreline; the addition brings the total to 2,000.

He said the purchase fitted with the conservation organization’s priority of some years’ standing of acquiring land around Cape Pogue Bay.

“For a start it’s very scenic, and secondly it’s such a rich shellfish fishery. We want to do what we can to keep septic systems from impacting its waters,” he said.

“So for the past five years or so we’ve been purchasing shoreline properties.

This property sat at the northern end of those we had already, so was a logical extension.”

So logical, in fact, that the land bank will have minimal work to do on its trail system.

“One of the remarkable things about the property is that there are already trails on it,” Mr. Lengyel said.

“There is a trail that connects out to the North Neck Road. There is a trail around that beautiful pond in the middle, although there is a part of it that needs a bit of work. We will continue to use the existing trail head next to the cemetery, and we’ll create a trail connecting it over to the property and linking into the existing system.”

Formal negotiations for the sale began last November, he said, “but we had our eye on it for a long time.

“It’s been plain all along that this is a very conservation-minded family, and they were very interested in working with the land bank to buy this property. We can tell when we’re working with a really conservation-minded seller and when it’s not, and this is a conservation-minded seller.”

The existing conservation restriction would not allow hunting on the land, but all other public uses of the land would be permitted in line with normal land bank practices.

The land bank will collaborate with the Chappaquiddick open space committee, which has offered to conduct a fund-raising campaign to help offset expenses.

On past experience, the land bank can expect a substantial contribution.

“The open space committee is a remarkable group of people, who have raised a remarkable amount of money for us,” said Mr. Lengyel.

“At the Quammox Preserve, for example, they raised $250,000 of the $2.1 million purchase price. For another of the properties which went into this Three Ponds preserve, one of the lots right there on Cape Pogue Bay, they put in $100,000.

“There are properties on Chappaquiddick that we never have purchased but for the fact the open space committee was providing capital for us.

“It would be wonderful if every neighborhood on Martha’s Vineyard had such an organization.”