John Cummins (Jack) Hathaway, a retired geologist with the U.S. Geological Survey and a longtime Oak Bluffs seasonal resident, died peacefully at his Falmouth home on Friday, Sept. 8. He was 95.

He was one of the founders of the U.S. Geological Survey Coastal Marine Geology Science Center in Woods Hole.

Jack was born in Hudson, N.Y. on Nov. 23, 1927, the son of Thomas H. M. Hathaway and Harriet Cummins Hathaway. He attended the Massachusetts Institute of Technology from 1945 to 1947, studying in the marine engineering department. In 1950, he graduated magna cum laude from Colgate University with high honors in geology. He was a member of Phi Beta Kappa. He received his master of science in geology in 1952 from the University of Illinois.

During his undergraduate and graduate years, his extracurricular activities included singing, crew, skiing and playing the tuba. He earned his private pilot rating and license for single engine planes and gliders.

During the summers from 1948 to 1951, he worked as a field assistant for the U.S. Department of the Interior, Bureau of Land Management, in Alaska, and the U.S. Geological Survey (USGS) in South Dakota, Wyoming and Montana. He joined the USGS in 1952 as a specialist in clay mineralogy and electron microscopy and became the chief of Sedimentary and Petrology Laboratories in Maryland and Colorado.

His career in marine geology included cruises along the Atlantic continental shelf. He participated in dives in the deep-submergence oceanographic research submarine (DSRV) Alvin up to a mile deep. His oceanographic research included cruises on the U.S. continental shelf and the Red Sea with visits to Ethiopia, Saudi Arabia and Djibouti.

He was the chief scientist for the Atlantic Margin Coring Project of 1976 and a delegate to the 1980 NATO conference in Portugal on sea floor slumping. In 1983, he was an advisor to the geological survey of Bangladesh.

From 1986 to 1989, he was the chief consultant for the U.S. Geological Survey’s Asia Development Bank contract in Bandung, Indonesia. There, he helped the Indonesian government establish a marine geological institute.

In the course of his geological career, he visited more than 39 countries and all continents except Antarctica, and made four trips around the world. He and his wife, the late Ilene Everhart Hathaway, RN, retired to their home in Falmouth in 1994.

During summers he made frequent forays to the Oak Bluffs cottages of his childhood. There, on the Highlands above Sunset Lake overlooking the harbor, his grandmother, Susan Ogden Cummins, had begun staying with her sister in law, Dr. Mary Gamble Cummins — the country’s first female homeopathic doctor — in 1928. His grandmother bought her own Highlands cottage in 1931. It was during visits to one or the other of the cottages that Jack developed his love of the sea.

With his childhood friend, the late John E. Meras, an East Chop summer visitor, there were frequent all-day sails to Cape Pogue, the Elizabeth Islands, or Woods Hole in John’s Manuel Swartz-Roberts-built catboat, Ted. Or there would be flounder-fishing days in the Middle Ground off West Chop.

In later years, Jack had his own boat, a 34-foot ketch named Fantasia that he kept moored in Woods Hole. Though he sailed less in his later years, he continued to be a downhill skier into his late 80s.

Jack is survived by his sister, Betty-Lisle Swanson of Bloomfield, Conn.; a daughter, Debra Foster, and her husband David of Dunbarton, N.H.; a son, David, and his wife Jane of Tucson, Ariz.; a son, Martin, and his partner James Warren of Oviedo, Fla.; a daughter, Alicia Buccino, and her husband Michael of North Falmouth; and Wie Gie Lim of Falmouth; and six grandchildren: Caroline Foster and her husband Ludwig of Luxembourg, Kimberly Alfonso and her husband Gary of Eustis, Fla., Christopher Buccino and his wife Caroline of Falmouth, Juliana Buccino and her husband Matthew Starkey of Falmouth, Michael Buccino of Pensacola, Fla. and Lilia Buccino of Tampa, Fla.; five step grandchildren, Matthew, Melissa, Heather, Aron and Abram; 13 great-grandchildren; one great-great grandchild; and several nieces and nephews.

He was predeceased by his wife, Ilene, and grandsons William E. Foster and Nicholas H. Buccino. The family is grateful to his caregivers, Katie Baxter and Pam Teixeira of Falmouth.

Visiting hours will be held Friday, Sept. 15 at the Chapman Funeral Home in Falmouth from 5 to 7 p.m. A celebration of life will be held at a later date.

Memorial contributions may be made to the Falmouth Service Center or to a charity of choice.

For online condolences, please visit chapmanfuneral.com.