In the book's own words, not ours, with obvious scanning errors fixed. Families often supplied these stories to the publisher, so check key dates.
Born 1826, German Township
From The History of Clark County Ohio, (1881)
MARY SPENCE, farmer; P. O. North Hampton; was born in German Township, Fayette Co., Penn., Oct. 18, 1826, and came West to Clark County in 1837. At the age of 24 years she united her destinies with Mark Spence (deceased), who was born in Cincinnati, Ohio, on the loth of September, 1820. On the 25th of December of the same year, he moved with his parents upon the farm his wife now occupies. Their union was blessed by the birth of a son, on Jan. 30, 1852. He resides at present with his mother, and is indeed all she desires. Politically, Mr. Spence was a stanch Whig; his first vote was cast for Henry Clay. The Whig party having been disruptured and the Republican party organized, Mr. Spence joined the latter party, and has ever since given it a hearty support. He was not a church member, yet he contributed liberally to the maintenance of religious interests. He believed that the interests of society and government are linked with the success of the common schools, and used his influence in their encouragement and support. Appreciating the value of good roads, Mr. Spenee urged their construction, and liberally lent his time and gave his money to that end. As evidence, from a total cost of a single turnpike, of $7,500, his contribution amounted to about $1,200. Jan. 8, 1878, Mark Spence departed from this life, leaving an only child to care for the bereaved widow. He was married on the 12th of February, 1880, te Miss Anna Friermood. ‘They have one child, born Jan. 15, 1881.
As printed in The History of Clark County Ohio, (1881). See the original pages. Wording is the original; obvious scanning errors have been corrected, and a few may remain.
Their biographies name Mary Spence: Sidney Grant Baker (b. 1872)
The printed record stops around 1881. We trace your line from there down to you, with every source cited.