Stop #2 - Brenton Point

History:

The Brenton’s Reef lightship was stationed here in the last century to warn of dangerous shoals and hidden reefs just off the coast. The reef takes its name from a prominent Newport family who had an interesting connection with the area. During the British occupation of Newport during the Revolution, Jahleel Brenton, a Tory, entertained Lieutenant Stanley, a British officer, in his home. Stanley noticed that Brenton’s adopted daughter Alice resembled his younger sister who had left England years before and been lost at sea. They were amazed to discover that Alice was indeed Beatrice Stanley whom the Brentons had saved as a child, the sole survivor from a wreck on the reef.

Description:

This outcrop is located in Brenton Point State Park on Ocean Avenue, just south of Pirate Cove and north of Collins Beach and represents a Precambrian-Cambrian unconformity. On this view point and northward are well-graded beds of the Castle Hill Member of the Newport Neck formation developed in a large overturned syncline. An F2-fold on the southern face of a small island (250ft; 75m long) can be viewed to the north across Pirate Cove.

Southward along the coastline the Lower Cambrian limestones and phyllites are exposed. The unconformity, best observed at low tide, is exposed at the base of the nearby cliff that forms the south slope of this viewpoint, and is located south of Pirate Cove and north of Collins Beach (Figure 1). The Precambrian rocks at this locality strike approximately N60ŻE and dip at a shallow angle toward the northwest. They are intensely and recumbently folded. Extensive exposures of the limestone beds are observable on the next point south, as is an unconformity with coarse Precambrian turbidite sandstones. Although complexly folded by F2-folds, two distinct limestone layers can be identified. Shell debris has been identified within both horizons, which on preliminary investigation appears to represent pre-trilobite Lower Cambrian fossils (E. Landing, personal communication, 1986). Large, east-west trending isoclinal recumbent folds repeat the limestone layers. A pervasive S2-slaty, low-lying cleavage, the dominant fabric over the Lower Cambrian succession, is axial planar to such folds. This cleavage is locally and broadly warped by north-south-trending F3-folds. Box folds and kink bands trending north-south to northeast-southwest deform the cleavage domains still further, and appear related to late-stage brittle faulting, probably associated with Alleghanian deformation.