I found the following excerpt in the site "Defiance County
Ohio Genealogy Trails,A part of the Genealogy Trails History Group. It was orginally published in Defiance County Biographies (Commemorative biographical record of northwestern Ohio, Chicago: J. H. Beers & Co., 1899).
I am vaguely related to many of the old Quaker families from New England, not a Slocum expert. But this excerpt seemed to have details that others might find useful.
"The subject of the article was CHARLES ELIHU SLOCUM, M. D., PH. D., and his Slocum ancestry is given in some detyail that might be helpful to others.
Charles Elihu Slocum, M. D., Ph. D., physician, banker and philanthropist, of Defiance , Ohio , is of pure English ancestry, the ancient home of his race being near Taunton, Somersetshire, England.
The founder of the branch in the United States from which our subject descends was one Anthony Slocombe, who came to America with his wife and family at the time of the absolute and despotic reign of King Charles L, and was one of the first purchasers in 1637 of several townships of land around the present site of Taunton, Massachusetts, which town he helped to found. It was in the records of this purchase that the clerk gave the present spelling to the surname. American marriages have kept the blood of the descendants of this first American ancestor in pure English lines.
The direct ancestors of Doctor Slocum, covering eight generations in America, are as follows: Anthony's son Giles, born in England, was a young married man when he came from his native country, his wife's given name being Joann. He was prominent in the colony of Rhode Island , as a man of large possessions, and was also a leading member of the Society of Friends, the family affiliating with that religious body on its first appearance in New England in 1656. The descendants continued in that relation until after the Revolutionary war, when removal to eastern New York widely separated them from the Society. Giles and Joann Slocum had a family of nine children, the youngest of which was a son, Eleazer, born the 25th day of "10th month," 1664, in Portsmouth , Rhode Island. He became a resident of Dartmouth,Massachusetts,in1684. He married Elephel Fitzgerald, and one of their sons, also named Eleazer, born January 20, 1694, married Deborah Smith, and had a son, John, born August 4, 1717, who became a yeoman and trader. He married Deborah Almy, and had a son, Eleazer, born May 15, 1744, in Dartmouth , Massachusetts , who married Anstace Viall, and this couple, after the Revolutionary war, removed with their family to what is now known as Northville, Fulton County, New York, which remained the family home for many years. Joseph, the eldest son of Eleazer and Anstace Slocum, was born February 6, 1766, in Dartmouth, Massachusetts, and was married in Cambridge, New York, to Elizabeth Wright in 1790. Their second son, Caleb Wright Slocum, our subject's father, was born in Northville, New York, October 22, 1797, and died there in 1864. He was a man of strong character and high standing, and was engaged in various business enterprises, being a farmer, merchant, tanner and manufacturer. His wife, Elizabeth (Bass), was born at Northville, November 25, 1798, and died there in 1866. Coming now to the ninth generation, we return to our subject, who is also a native of Northville , New York, born December 30, 1841. His early education was obtained with the aim of preparing himself for teaching and general business, his studies being pursued in the schools of his native town, and by his own exertions in Fort Edward Collegiate Institute, and at Poughkeepsie , New York. Several years of his early manhood were passed partly in attending school and partly in teaching in public and private schools with ascending grades. His services were also in demand as instructor in teachers institutes."