There was a Jellis Beemer who was baptised in the Reformed Dutch Church of Caughnawaga on 16 Jan 1774; his parents were given as Philip Beemer and Catrina Lyserin (my guess Lyser).
My ancestors, Stephan Jordan and Margaret Bellon, had a son who was baptised at this same church; the sponsors were Philip Beemener and Catherine(sp).
Do you believe, as I do, that these people match yours?