The charioteer (61) and apobates (hopite-athele) (62) stand on the diphron (enclosed platform) of the chariot. The latter is wearing a long chiton with straps tied crosswise to facilitate movement. Unlike the other apobates, he carries his shield on his back and is wearing religious clothing. He has been identified as Erechtheus, the mythical founder of the chariot race of the apobatai. 

The next block (N XXII) has been lost, though it is believed that it depicted chariot horses.

Half of the North frieze is in the British Museum and the other half in the Acropolis museum. The total length of the north frieze was 58.70 m. The scenes begin at the northwest corner of the opisthonaos as a continuation of the procession which has already started on the west side, thus running from block N XLVII to block N I. The action develops gradually and from quiet preparation accelerates to a gallop. Ignoring the divisions of the blocks, the horsemen are depicted proceeding in groups of seven or eight, the horses partly overlapping each other. The continuous flow of horses and riders is interrupted only by the marshal (90) on block XXXIV. Yet with variety of garment, of stance and gesture of the most beautiful of the horsemen and with the occasional depiction of a man turning his head to look back, monotony is avoided. The frieze of the Parthenon forms a continuous band with scenes in low relief that encircles the upper part of the cella, the main temple, within the outer colonnade. The theme represented was the procession toward the Acropolis that took place during the Great Panathenaia, the commemoration of the birthday of the goddess Athena.
Numbering taken from I. Jenkins, The Parthenon Frieze, 1994. Frieze slabs are marked in Roman numerals, People are marked in arabic numerals.