RJ: she is possibly listed in an obit in The San Francisco Examiner3 Dec 1982Public records have her in Sonoma, CA
This is the family in 1901:http://www.census.nationalarchives.ie/pages/1901/Londonderry/Swatragh/Upperlands/1545901/The same family in 1911:http://www.census.nationalarchives.ie/pages/1911/Londonderry/Swatragh/Tirgarvil/611932/
Further to the parents of the Thomas S. Cassidy identified at Reply #2, the closest fit I can see thus far for Thomas S., is a child registered at Kilrea subdistrict (Ballymoney district) as just 'Samuel' Cassidy, born on 16 March 1885 to parents William Cassidy and Margaret Mullan of Drumard (could it be that he was maybe baptised as Thomas?):https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1885/02650/1977021.pdfThis is the family in 1901:http://www.census.nationalarchives.ie/pages/1901/Londonderry/Swatragh/Upperlands/1545901/The same family in 1911:http://www.census.nationalarchives.ie/pages/1911/Londonderry/Swatragh/Tirgarvil/611932/William Cassidy and Margaret Mullan were married in 1876, their address was Killygullib, the two fathers recorded as Manus Cassidy and John Mullan, both labourers:https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1876/11181/8097130.pdfI'm guessing that their marriage address is the townland of Killygullib Glebe, a neighbouring townland of Drumard in the civil parish of Tamlaght O'Crilly, ie...Killygullib Glebe:https://www.townlands.ie/londonderry/loughinsholin/tamlaght-ocrilly/hervey-hill/killygullib-glebe/Drumard:https://www.townlands.ie/londonderry/loughinsholin/tamlaght-ocrilly/tamlaght/drumard/As parents for William Cassidy, I wonder about the following folk who got married in 1851... Manus Cassidy and Jane McAllister of Bovedy (another neighbouring townland of Killygullib Glebe), the two fathers recorded as Francis Cassidy a farmer and John McAllister a schoolmaster:https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1851/09402/5405878.pdfBovedy:https://www.townlands.ie/londonderry/coleraine/tamlaght-ocrilly/hervey-hill/bovedy/
Martha McLatchey was born at Culdoo Upper townland in the civil parish of Ballymoney on 16 January 1879 to parents David McLatchey and Mary Trimbles:https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1879/02934/2074944.pdf David McClatchy married Mary Pollock nee Trimble in 1876, both were widowed and living in Culduff (Culduff = Cul dubh = Culdoo), the two fathers were recorded as David McClatchy and James Trimble, both farmers:https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1876/11181/8097149.pdfCuldoo Upper:https://www.townlands.ie/antrim/dunluce-upper/ballymoney/enagh/culdoo-upper/ This looks like Martha's mother and several siblings in 1901:http://www.census.nationalarchives.ie/pages/1901/Antrim/Enagh/Culdoo_Upper/942676/Martha McClatchey married William Campbell in 1902:https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1902/10269/5737579.pdfPerhaps a son Joseph Alexander Campbell born to William and Martha in 1903?https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1903/01853/1722225.pdf