references in FW are mostly limited to the prankquean vignette, and the 2nd paragraph
003.04 "Sir Tristram, violer d'amores, fr'over the short sea, had passencore rearrived from North Armorica on this side the scraggy isthmus of Europe minor to wielderfight his penisolate war"
004.07 "Sanglorians, save!" (Saint Lawrence?)
021.12ff "Tristopher and Hilary" (the name of the heir kidnapped by Grace O'Malley was Christopher St Lawrence, later to be the 10th Baron Howth)
022.12 "that laurency night"
211.25 "a change of naves and joys of ills for Armoricus Tristram Amoor Saint Lawrence"
?312.18 "feared crimp or cramp of shore sharks, plotsome to getsome. It was whol niet godthaab of errol Loritz off his Cape of Good" (it was surely not a good hope of Earl Lawrence their telling told, but it was surely a bargain what he always allowed of the customers)? (Earl Lawrence, Saint Lawrence family, Earls of Howth)?
616.34 "must close hoping to Saint Laurans all in the best"
Sir Armoricus Tristram, of Normandy (??-1189) [cite] Amory? 
Sir Amory Tristram, called "St. Lawrence," created Baron Howth, d1189  Armory? 
brother-in-law Sir John Courcy 
possibly descendant of Roger de St. Laurent, who accompanied William the Conqueror in 1066? [cite] (wouldn't this contradict origin of St Lawrence name?)
defeated Irish on 10 August 1177 (St Lawrence's day) (one of the last battles of the Anglo-Norman invasion under Henry II [eb] that started in 1169)
estate granted 1177, continuous possession of family since 1177 
(last king of Ireland, ROC, died 1198)
abbey c1235 
family name variously cited as Amory, Amorey, Armory, Armoricus, Almeric, Almericus, Americus
'Tristram' was presumably family name in Normandy, dropped and substituted 'St Lawrence'?
motto? 'Que pense' 
family line mostly named Nicholas, Adam, Robert, Christopher, Thomas, William
Nicolas Fitz Amorey (???) [cite] FitzAmory St Lawrence, 2nd baron 
Almericus de St. Lawrence (???) [cite]
Nicholas St Lawrence (???) [cite] ? 
Adam Saint Lawrence (???) [cite]
another Adam Saint Lawrence (1305-1334) [cite]
Nicholas St Lawrence (c1350-1404) [cite]
9th baron Almericus?  died 1327? 
Stephen or Christopher St Lawrence, 1st Baron Howth (1368-1435) [cite]
Christopher Saint Lawrence, 2nd Baron Howth (1406-1462) [cite]
Robert St Lawrence, 3rd Baron Howth (c1431-1486) [cite]
Nicholas St Lawrence, 4th Baron Howth (c1456-1526) [cite]
Christopher St Lawrence, 5th Baron Howth (c1485-1542) [cite]
Edward St. Lawrence, 6th or 5th Baron Howth (c1508-1549) [cite] (brother of Christopher St Lawrence, 8th Baron Howth and Richard St. Lawrence, 7th or 6th Baron Howth; father of Richard St. Lawrence; Anne St. Lawrence and Alison St. Lawrence)
Richard St. Lawrence, 7th or 6th Baron Howth (d1558) [cite] (brother of Edward St. Lawrence, 6th or 5th Baron Howth and Christopher St Lawrence, 8th Baron Howth)
Christopher St Lawrence, 8th Baron Howth (c1509-1589) [cite] (brother of Edward St. Lawrence, 6th or 5th Baron Howth and Richard St. Lawrence, 7th or 6th Baron Howth; father of Nicholas St. Lawrence, 9th or 8th Baron Howth and Elizabeth St Lawrence)
Nicholas St. Lawrence, 9th or 8th Baron Howth (c1555-1607) [cite] (father of Sir Christopher St. Lawrence, 10th or 9th Baron Howth; Margaret Plunkett and Alison Luttrell b1580)
1576: Grace O'Malley kidnaps grandson/heir [wiki]
Sir Christopher St. Lawrence, 10th or 9th Baron Howth (c1576/1568-1619) [cite] [wiki]
Thomas St Lawrence, 12th or 11th Baron Howth (c1599-1649) [cite]
William St Lawrence, 12th Baron Howth (1628-1671) [cite]
Thomas St Lawrence, 13th Baron Howth (1659-1727) [cite]
William St Lawrence, 14th Baron Howth (1688-1748) [cite]
Robert, 15th baron? 
Thomas St. Lawrence, 1st Earl of Howth (1730-1801) [cite]
William St. Lawrence, 2nd Earl of Howth (1752-1822) [cite]
Sir Thomas St. Lawrence, 3rd Earl of Howth (1803-1874) [cite]
the 1909 map shows a region called 'Saint Laurence' southwest of Chapeizod