A historic boulder in Rochester, supposedly marked by the devil himself, and the stone surrounding it are causing problems for a proposed solar farm slated to be built on Mattapoisett Road.

Called "Devil's Rock," the landmark supposedly features a footprint that early settlers thought was left by the devil. When the project was proposed, abutters and the Rochester Historical Society argued that the rock should remain protected from any construction. The Planning Board agreed, and provided that stipulation in its approval of the solar farm.

It turns out, the board learned Tuesday, that the rock is part of a larger rock outcropping, which was only discovered by Clean Energy Collective after the solar company began digging at the site.

There has been a cease-and-desist on construction at the site, located at 268 Mattapoisett Road, since the discrepancies were discovered and reported to the Planning Board.

Instead of the 300 cubic yards of material that the company intended to and was approved to remove via controlled blasting, it may have to remove as much as 1,300 cubic yards, thanks to the additional rock uncovered around Devil's Rock.

That requires Planning Board approval, but members were concerned about such a significant change to the original plan.

"The grades have changed significantly and the stormwater management [the company] proposed won't work if they don't get the rock outcropping down to the approved levels," explained Ken Motta, the town's consulting engineer. "It needs a whole new regrading plan, because I have nothing to go on."

Clean Energy project manager Doug Carton told the board that he was hoping to get approval for the additional rock removal on Tuesday.

"We're working on a very tight schedule," he said. "I'm hoping you'll approve the changes intended to get to approval standards without a new plan, so we can move on this as soon as possible."

But Planning Board members were not willing to sign off on the change. Some said the company would need an engineer to create a new site plan. Another suggestion was to schedule a public hearing to allow residents to weigh in on whether the company should be allowed to blast additional stone.

Either way, a wait would be involved that likely would not fit into the company's timeline.

Noting that drafting a new site plan or waiting the required two weeks for a public hearing to be advertised would each result in a wait for the company, Planning Board member Ben Bailey had an another idea.

"Pick one" approach, Bailey said, "and in the meantime, send someone out to drill into the rock and see if you can get any of it removed with just a drill and a hammer. If you do that, we won't need a public hearing, and you can just continue."

Carton and Johnson both agreed with the idea. Johnson said he was willing to suspend the cease-and-desist order for contractors to test the hammer-and-stone theory only.

Meanwhile, Borrego Solar's plan for a solar farm at the intersection of Mendell and Rounseville Road faced less criticism from the board.

Borrego Solar representative Steve Long, the project's civil engineer, said that the plan for screening now included a five-foot stockade fence on top of a two-foot earthen berm.

"How sure are you that there are no rock ledges in the area, considering what we just heard?" asked Planning Board member John DiMaggio.

"We've dug and tested everywhere, even the wooded areas," Long assured him.

"I like your method better," DiMaggio reasoned.