...The walls would be more apt to fall outwardthan inward, and would be more liable to crumble than to fall as anintact mass... 
Gerard Fowke 「Archeological Investigations」
...Unmortared cellar walls are frequentlylaid under wooden buildings, and pointed with lime-mortar inside;but this is sometimes dug out by rats, and is apt to crumble and fallout otherwise...
Lewis Falley Allen 「Rural Architecture」
...All the towers now stand out in boldrelief,—as if they were just about to crumble into the seething massbelow...
Elise Whitlock Rose 「Cathedrals and Cloisters of the South of France, Volume 1」
...It is in this last formation,which is so soft that it can be easily hollowed out, and yet so solidthat it does not crumble, that the Catacombs are invariably found...
Hugh Macmillan 「Roman Mosaics」
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