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I located a 1902 baptismal record for John Conlon on the subscription site Roots Ireland. See below.
I located the December 24th 1900 civil marriage record for Thomas Conlan and Catherine Kilwee. The marriage was held in the Templeboy RC church which would have been the bride's parish. Thomas' father was Pat and Catherine's father was John.
I did find the family in the 1911 census in Ballyglass. There were only two sons John and Patrick. The census form showed that Catherine had five children but one died. http://www.census.nationalarchives.ie/pages/1911/Sligo/Dromore/Ballyglass/768697/
I checked further for civil birth records on the free site www.irishgenealogy.ie and located an August 5th 1905 record for James Conlan but did not find his death record. Likely hed was the deceased child reflected in the 1911 census.
Name:John ConlonDate of Birth:16-Feb-1902
Date of Baptism:22-Feb-1902Address:BallyglassParish/District:KILMACSHALGANGender:MaleCountyCo. Sligo
Sponsor 1 /
Informant 1:Thomas Flatly Sponsor 2 /
Informant 2:Bridget Mullarky