Adam Clarke, on Gen 11:3

“And each one said to his neighbour: Come, let us make brick, and bake them with fire. And they had brick instead of stones, and slime instead of mortar.”

“Let us make brick - It appears they were obliged to make use of brick, as there was an utter scarcity of stones in that district; and on the same account they were obliged to use slime, that is, bitumen, (Vulg). ασφαλτος, (Septuagint) for mortar: so it appears they had neither common stone nor lime-stone; hence they had brick for stone, and asphaltus or bitumen instead of mortar.”

Imported from an open dataset — not yet checked against the printed edition.