Parallel walls find mention in two places in the Annual Report of the Archaeological Survey of India 1924-25 (published 1927) [hereafter ARASI 1924-25].

Sahni: “During the season 1924-25 excavations were continued at the low mound Northern F in General Cunningham’s plan, which adjoins the bank of the old bed the river Ravi and the lofty mound A-B which rises abruptly to a height of 60’ immediately to the south of the above mentioned mound. I excavated for four months from the 6th December 1924 to the 6th April 1925, the total cost of the operations amounting to Rs. 13,000 against Rs. 3,000 spent in the preceding year. The buildings brought to light are some 'what better' preserved than those disclosed in the previous excavations and include what appears to have been a temple with stout brick walls in mound B (Plate XXV, b) and another large-sized structure (Plate XXIV, c), consisting of a double series of parallel walls without connecting walls of any land, unearthed in mound F. The exact purpose and nature of the latter building are not yet ascertainable.” (p. 74)

Sahni noted that the “most important architectural discovery” of the year was made in Mound F, which is “the existence of two solidly built walls running parallel to each other without any party walls which had been brought to light here in the preceding year, but the exact meaning of which could not be ascertained. With these walls as a starting point, the excavation was taken in hand and great was my surprise when the operations continued to reveal, in quick succession at narrow intervals, wall after: wall, until I had a series of 14 of them, all running parallel to each other and of the same length namely 51 '9". (p. 76)

The above area, of “wall after wall” was subsequently described in detail by Vats as the Great Granary. For details, see photograph 64.

- Daya Ram Sahni, ARASI 1924-25, pp. 74, 76.

NOTE:
Photos Block of Parallel Walls, Block of Parallel Walls and Harappa Walls are of the area of Parallel Walls before deep digging.