Unfortunately I do not have any information on the parents of James Douglass or Margaret Clarke.A correspondent in Ireland did find a mention of James Douglass in a letter which is in the PRONI file D/2547/22 (in Ireland) written by William G. Douglass on April 13, 1908 - The entry in the old family bible is in father's handwriting - "Rev. James Douglas, Church of England, Newton Limavaddy."
The following book is where I found a good portion of the information about Jackson Douglass’ branch of the family:"A Collection of Family Records with Biographical Sketches bearing name Douglas" by Charles Henry James Douglas, E. L. Freeman & Co. Publishers, 1879.Perhaps the Library in Alexandria might have this book?If not, it is accessible via a subscription to GenealogyLibrary.com.
In the above-mentioned book is says: "Jackson Douglas came to America with his parents in 1798, and died soon after, in Baltimore, MD leaving children, James, Jacob Davies, Samuel and Sarah Glen Douglas."My correspondents and I searched high and low for information on Jackson’s death or anything about his parents but as yet have found nothing.
I did find a newspaper notice of Jacob Davies’ wife’s death in the Baltimore American, 23 August 1813:“DAVIES, Mrs., relict of the late Rev. Jacob Davies, Presb. clergyman from the North of Ireland, died Sat,. 22 inst, in her 74th year.”
Also: Belfast News Letter 16th January 1787; Matriculation Album of Glasgow University: “DAVIS, Rev Jacob - the only son of William DAVIS, County Londonderry, was educated at Glasgow from 1756, licensed by Derry Presbytery 1762, ordained at Drumachose, Limavady, County Londonderry 26th April 1763, and died 30th December 1786."A man of the most genuine, unaffected piety, meekness and integrity."
I believe Reverend James Douglas and wife Margaret Clarke had the following children (order not known) but sorting them out was challenging and may still not be 100% accurate: Jackson, Samuel, Janet, Ann, Elizabeth, Margaret, Rebecca, Jane, James, Jacob
From which of Jackson Douglass’ children does your family line descend?I'm connected to in-laws of two children of Jackson Douglass' son James -- Stuart R. Douglass and Eliza Kincaid Douglass.