Church and chapel data from The Religious census of 1851 : A Calendar of the returns relating to Wales, Vol 11, North Wales. Ed. by Ieuan Gwynedd Jones, UWP,1981. The names given towards the end of each entry are those of the informants.
Tref-llys Parish; Statistics; Area 999 acres; Population 58 males, 45 females, total 103
All Returns are missing for this District
Rees, Thomas & John Thomas. Hanes Eglwysi Annibynnol Cymru(History of the Welsh Independent Churches), 4 volumes (published 1871+). Here is the entry from this book for Treflys chapel (in Welsh ) - with translation by Eleri Rowlands (Sept 2009)
Alltud Eifion Papers - details of extant records on Archives Network Wales
"Include; ............ A sunday school minute book for Brynmelyn (C. M.) Chapel in Treflys, Caernarfonshire 1819, 1824 and 1827......"
TREVLYS (TREV-LYS, or TREV-LLYS), a parish in the hundred of EIVIONYDD, county of CARNARVON, NORTH WALES, 3 miles (S. W. by S.) from Tremadoc, containing 78 inhabitants. It is situated on the northern shore of Cardigan bay, and is but of small extent. The living is a perpetual curacy, annexed to the rectory of Criccieth, in the archdeaconry of Merioneth, and diocese of Bangor. The church, dedicated to St. Michael, is a small ancient edifice, without any architectural claim to notice, and is in a very dilapidated state. There are places of worship for Independents and Methodists. Poor children of this parish are eligible to the free school at Criccieth, founded by the Rev. David Ellis. The average annual expenditure for the relief of the poor amounts to £ 19. 13. (A Topographical Dictionary of Wales by Samuel Lewis, 1833)