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John Caldwell b 4 July 1803 at Maxwood m 18 June 1826 Janet Hunter
Children:
Janet 1827
John 1828
Allan 1831

Allan and Janet emigrated to Sydney Mines, Cape Breton Island, Nova Scotia about 1832, Allan was unfortunately killed in a mining accident in 1835.
Janet remarried to Allan Parker at Saint George, Sydney, Cape Breton Island on 22 January 1836. Some of their descendents went to Boston and Montreal but others still live in that area.

John Caldwell (son of John Caldwell and Mary Morton (his first wife) b 1811 at Galston m Anne Woodburn (this is problematical because there was another John Caldwell (son of William Caldwell and Elizabeth Breckenridge in the area at the same time)
Children of "John Caldwell" and Anne Woodburn:
William (1829-?) (married Ellen McCallum)
Christina (1833-1902) (married George Sharp)
John (1834-1835)
Mary (1836-1912) (married Thomas Martin died Oskaloosa Iowa)
John (1838-?)
James (1840-?) (married Anne Steel)
Allan (1842-1869) (married Mary Nisbett) (died Bentinck Terrace - humous abcess 12 months)
Ann (1845-?) (married Thomas Clark)
Robert (1849-?) (married Elizabeth Mitchell)

children of "John Caldwell" by Martha Yeudall:
Jean (1855-?)
Agnes (1857-?)
Martha (1859-?)
Jean (1862-?)
Isabella (1866-?)

There may be more than one John Caldwell involved here and any help to untangle this would be appreciated.

The John in the 1831 census is more likely to be the father of the above named:

John Caldwell b St Quivox 25 February 1780 (parents Allan Caldwell and Janet Guthrie) m (1) Mary Morton (date/place unknown) paper maker at Straith Mill - later "labourer" died at 5 Kilnknowe 4 February 1855
Children:
Allan (1803 Maxwood -1835 Sydney Mines) (see above)
Matthew (1804 Straithmiln -1849 Riccarton) m Helen Walker - moved to Riccarton (my ancestors)
Mary (1806 Little Maxwood-1848) married Samuel Wallace
Janet (1807-1848)
Jean (1809 Straithmiln -1854) m(1) James Templeton ??? 1826 (2) Malcolm Kerr 1828
John (1811-1869 Henrietta Street Galston) (see above)

Children of John Caldwell & (2) Agnes McClanachan (married 23 May 1815)
Agnes (1816-1817)
David (1823 Galston - 1908 Temple Street Darvel) (married Isabella Robertson) 10 children - 3 Isabella's
Elizabeth (1825-?)
Ann (1829-?) (married John Robertson 15 June 1850)
Janet (1832-1849)

Notable is the grouping of the dates of death - Galston and district had epidemics of cholera and smallpox in these times.

The widow may have been Elizabeth Caldwell (Breckenridge) the former wife of William Caldwell who does not seem to be related - amongst their children was another John Caldwell and an Isabella who married a Yeudall.

There was also yet another John Caldwell m Janet Mair living in Loudoun parish at about the same time - they had a whole tribe of boys - that John must have been about 10-15 years older.