From Watson's Annals: "Most Philadelphians have had some vague conceptions of the caves and cabins in which the primitive settlers made their temporary residence. The caves were generally formed by digging into the ground, near the verge of the river-front bank, about three feet in depth; thus, making half their chamber under ground, and the remaining half above ground was formed of sods of earth, or earth and brush combined. The roofs were formed of layers of limbs, or split pieces of trees, over-laid with sod or bark, river rushes, &c. The chimneys were of stones and river pebbles, mortared together with clay and grass, or river reeds."