Wilfred J. Caron was a quizzical man. He owned a Christmas tree farm in Old Mystic, Conn., right on U.S. Route 1. His ramshackle house was painted pink, with green signs out front, an old cemetery nearby, and new housing development crowding the land on all sides. When I met Mr. Caron, his Christmas trees had grown beyond the reach of his shear and were fast becoming a forest.

Antiques filled his house. We spoke amid glass globes and hanging silks and swords displayed by the fireplace. We were speaking about his land and how he could conserve it. I was holding forth on this subject, when he stopped me. Leaning forward, he raised an eyebrow, looked at me intently, and said, “Ah, but did you see the erratic?”

The erratic. Indeed I had seen it. An enormous boulder, the erratic lay near the northern edge of the property. Sitting amid the spruces, it dwarfed every other rock on the property. The erratic had caught Mr. Caron’s fancy, and it was what he loved most about his land.

“Erratic” is an apt term. Erratics are boulders, large ones. As they are so much larger than the other stones on a given piece of land, they seem out of place, and appear to have been deposited in error. On Martha’s Vineyard, erratics can be found along the up-Island moraine. Their presence here is no error; the glacier brought them here. Yet despite the logical explanation for their presence, erratics still instill a sense of wonder.

Glacial erratics have long played roles in the culture and the history of Martha’s Vineyard. Waskosim’s Rock, for example, is a large erratic found at the land bank’s Waskosim’s Rock Reservation. Waskosim’s Rock served as a landmark on the Middle Line, a line that once divided the Mayhew lands to the east from the Wampanoag lands to the west. Other erratics also bear names. At Peaked Hill Reservation, for example, you can find the Wee Devil’s Bed and Stonecutter’s Rock.

There are, of course, many other erratics, found here and there across the moraine. All of them are worth the walk to see, and many invite climbing. No visit to Waskosim’s Rock Reservation is complete without a visit to the property’s namesake feature. At the A.S. Reed Bird Refuge portion of Cedar Tree Neck Sanctuary, one finds an enormous erratic alongside the White Trail. It is a steep ascent to reach the erratic, but once there, climbing the boulder itself is irresistible.

My favorite erratic is found at Middle Line Woods Preserve in Chilmark. One reaches it via a walk in either direction on the property’s loop trail. Even absent the erratic, a walk on this property is a pleasurable one, owing to the numerous American hollies alongside the path. Lying among the oaks, the erratic looks splendid. In the future, however, the oaks of today will have yielded the forest to American holly and American beech, and it is hard to image a forest scene more magnificent than that of this great boulder in the shade of the lustrous leaves of the evergreen holly.

The Middle Line Woods Preserve erratic is enormous, and there are other erratics on the property as well. I visited the preserve with my children. Upon reaching the erratics, the children knew instinctively what to do: climb. So they did, and with a boost here or there they made their way to the top and played King of the Mountain. I simply stood back, helped them climb up or down, and stood ready to catch them if they fell.

While watching the children play, it struck me how the simple sight of the erratic caused all of their complaining to cease. No matter what I try, my children groan upon being told they are going for a hike. They moan and complain — until they reach an erratic, that is, or until they reach the water. Then their mood changes instantly, and they climb and play and find amusement of all kinds.

There are many elements to the appeal of an erratic. First of all, they are simply big. Big things, be they rocks or trees or animals, attract our interest. Second, they call out to be climbed. They offer a challenge, and an exhilarating feeling to those who scramble to the top. There is some appeal to the feel of the cold stone and there is the visual appeal of stone encrusted with lichen and moss.

Erratics have another appeal. They are so out of place, yet are such distinctive, permanent features of our landscape. They are not going anywhere, and they cause the onlooker to stop and think. They demand consideration. Certainly, Mr. Caron found the very erratic nature of his boulder appealing. Perhaps he drew parallels to the erratic nature of his own land: a coniferous forest amid a sea of residential development. Perhaps there is some appeal in seeing these fragments of the White Mountains so lost, yet so at home, in our Island landscape.

Perhaps the wonder of the erratic is the wonder that it evokes.

Adam Moore is executive director of Sheriff’s Meadow Foundation.

Suzan Bellincampi is on leave.