Silvia,
I have info from the "Berkey Book" (by Ruth Berkey Reichley) for you...although you may wish to check out the info as well.
According to the book, your Jacob K. Berkey is listed in "Line 4" of Berkey folks. The initial entry lists a Christian BERKEY, b.1758; d.1828 who married a Gertrude KOLB /KULP. She died in 1840. The book mentins most of this line live(d) in Ohio. Chrisitan was a native of PA. (The book recommends a reference to "Kulp History" p.152)
Christian's family was 5 sons & 4 daughters. They were:
Jacob (1793-1880) m. Mary KOPPES (parents of Jacob K.);
Issac---never married; was crippled; a shoemaker;
Catherine---never married; lived with brother, Issac;
John BARKEY (1781-1860) a Mennonite minister, m. Susannah BUZZARD; (surname is spelled BARKEY)
Christian (1794-1872), m. Barbara SHAUM, m.2nd--Mary LANDIS;
Nancy; (I think this may be Rebecca, but not certain) otherwise there are 5 daughters...if I am counting correctly...
Rebecca;
Elizabeth;
Susannah (1790-1874) m. Rev. Samuel KOPPES;
Henry m. Julia KEISTER
Hope that helps. Glad to provide additional info if needed.
Sally Huntley