The facade is a fine example of Rayonnant Gothic for a part and, for the rest, Flamboyant gothic - as it existed in Ile de France (the area around Paris, the historic heart of France) .i.e. a form of Gothic deprived of the excessive and superabundant enrichments that can be found in the Flamboyant Gothic of Normandy , e.g. in St Maclou's in Rouen or in the porch of Our Lady's of Louviers, an exuberant tangle of sculptures.
Late Gothic( called 'Flamboyant', in French)
The general arrangement can evoke St James's in Dieppe or St Peter's in Caen (both in Normandy). A difference to be noted is that the portals of these churches are hidden behind gables, a usual ornament in the 15th century, which does not exist in Vernon.
The lower part of the facade goes back to the beginning of the 15th century, whereas the centre and the top were built somewhat later. Thus, we can see Rayonnant windows in the side aisles (on each side of the porch) while the Northern tower is definitely Flamboyant.
Coming soon: photo of lower windows and commentary
Right at the top, you will notice the circular arches of the powerful flying buttresses, which are also stiffened with struts. The arch connects to the buttress proper and transmits to it the thrust of the vault across the intervening space of a chapel: as a result, the wall, no longer having to bear thrust, can be opened up into huge stained glass panels.
More about flying buttresses
The main porch
The two doors, under two tierce-point arches, are separated by a trumeau (i.e. a pillar between the two doors) adorned with a statue of the Virgin with Child under a canopy.
It is not surprising to see that most of the decoration refers to the Virgin, since the church is dedicated to Her. In the middle, a beautiful, Norman-style, XIVth c statue of the Virgin with Child. The lintel illustrates some episodes of Mary's life (Annunciation, Visitation, Adoration of the Three Wise Men, Presentation of Jesus in the Temple). This bas-relief, signed F. Taluet, is dated 1866 and replaces a former one that was hammered away down during the French Revolution (at the end of the 18th century).
The porch itself is composed of two tiers of arching (unfortunately in a bad state of repair) with the statues of various figures from the Holy Scriptures, and the door jambs have niches that used to shelter the statues of the four Evangelists.
Between the porch and the first gallery, under the rose, you can see five arches with statues.
To go farther:
A few specialised pages...
How did the development of 12th c. philosophy affect architecture? How was it technically possible to build such high churches? How can you tell the date? Etc....