These seacliffs expose a thick succession of Upper Cambrian volcaniclastic rocks which contain subordinate beds of tuffs and dacitic and andesitic lava flows.

The uppermost layer of sedimentary rocks, exposed in these seaclifts, consists of 150 m (492 ft) of predominantly coarse-grained volcaniclastic turbidites.

The bedding is deformed by similar folds accompanied by cleavage and east-dipping thrust faults with displacements of few tens of meters.

The expedition set out in 1879 aboard the USS Jeannette, hoping to reach Wrangel Island and to discover open seas in the Arctic Ocean near the North Pole.

According to The Annual Report of the Secretary of the Navy, for the Year 1882,[3] "A sled party landed [on Henrietta Island], hoisted the national ensign, and took possession in the name of the United States.

[6] Some U.S. individuals assert American ownership of Jeannette Island, and others of the De Long group, based on the 1881 discovery.

However, the United States government has not pursued De Long's claim to Jeannette Island, and recognizes it as Russian territory.