It is an edifice of the transition period. The Saxon architect completed the erection of the first pillars of the nave， when the pointed arch， which dates from the Crusade， arrived and placed itself as a conqueror upon the large Romanesque capitals which should support only round arches. The pointed arch， mistress since that time， constructed the rest of the church. Nevertheless， timid and inexperienced at the start， it sweeps out， grows larger， restrains itself， and dares no longer dart upwards in spires and lancet windows， as it did later on， in so many marvellous cathedrals. One would say that it were conscious of the vicinity of the heavy Romanesque pillars.
However， these edifices of the transition from the Romanesque to the Gothic， are no less precious for study than the pure types. They express a shade of the art which would be lost without them. It is the graft of the pointed upon the round arch.
Notre-Dame de Paris is， in particular， a curious specimen of this variety. Each face， each stone of the venerable monument， is a page not only of the history of the country， but of the history of science and art as well. Thus， in order to indicate here only the principal details， while the little Red Door almost attains to the limits of the Gothic delicacy of the fifteenth century， the pillars of the nave， by their size and weight， go back to the Carlovingian Abbey of Saint-Germain des Prés. One would suppose that six centuries separated these pillars from that door. There is no one， not even the hermetics， who does not find in the symbols of the grand portal a satisfactory compendium of their science， of which the Church of Saint-Jacques de la Boucherie was so complete a hieroglyph. Thus， the Roman abbey， the philosophers' church， the Gothic art， Saxon art， the heavy， round pillar， which recalls Gregory VII.， the hermetic symbolism， with which Nicolas Flamel played the prelude to Luther， papal unity， schism， Saint-Germain des Prés， Saint-Jacques de la Boucherie，--all are mingled， combined， amalgamated in Notre-Dame. This central mother church is， among the ancient churches of Paris， a sort of chimera； it has the head of one， the limbs of another， the haunches of another， something of all.
We repeat it， these hybrid constructions are not the least interesting for the artist， for the antiquarian， for the historian.
They make one feel to what a degree architecture is a primitive thing， by demonstrating (what is also demonstrated by the cyclopean vestiges， the pyramids of Egypt， the gigantic Hindoo pagodas) that the greatest products of architecture are less the works of individuals than of society； rather the offspring of a nation's effort， than the inspired flash of a man of genius； the deposit left by a whole people； the heaps accumulated by centuries； the residue of successive evaporations of human society，--in a word， species of formations.
Each wave of time contributes its alluvium， each race deposits its layer on the monument， each individual brings his stone. Thus do the beavers， thus do the bees， thus do men. The great symbol of architecture， Babel， is a hive.
Great edifices， like great mountains， are the work of centuries.
Art often undergoes a transformation while they are pending， ~pendent opera interrupta~； they proceed quietly in accordance with the transformed art. The new art takes the monument where it finds it， incrusts itself there， assimilates it to itself， develops it according to its fancy， and finishes it if it can.