Paul's teaching is almost solely on the importance of baptism
John the Baptist and Jesus are the same figure
Secret Mark has baptism as the initiation ritual for the higher mysteries
The use of ships and anchors in early Christian symbolism, as well as Marcion's role as a "mariner", to emphasize the importance of water in the Gospels (baptism, Sea of Galilee, turning water into wine, sweating blood, water and blood gushing forth from Jesus, Paul's shipwreck, etc.)
Gospels indicative of certain primer features are known to have existed, (infancy, sayings, crucifixion, descent into hell, etc.) yet a Gospel about baptism is mysterious absent
Baptism is intrinsically tied to the deluge of Genesis 7-8 which begins a new dispensation