A method used in forming a memory array comprising strings of memory cells comprises forming a stack comprising vertically-alternating first tiers and second tiers. The stack comprises laterally-spaced memory-block regions. Channel-material strings extend through the first tiers and the second tiers. Material of the first tiers is of different composition from material of the second tiers. Conducting material is formed in one of the first tiers. The conducting material comprises a seam in and longitudinally-along opposing sides of individual of the memory-block regions in the one first tier. The seam is penetrated with a fluid that forms intermediate material in the seam longitudinally-along the opposing sides of the individual memory-block regions in the one first tier and comprises a different composition from that of the conducting material. Other embodiments, including structure independent of method, are disclosed.