How long the fall of dust lasted we can only infer from this, that when it ceased the sun had not yet set. In Misenum, which the shower of pumice stone had not reached, everything was covered with a thick layer of dust. Although the earthquake shocks continued, the inhabitants went back into their houses. But Pompeii and Stabiae had been covered so deep that only the roofs of the houses, where these had not fallen in, projected above the surface; and Herculaneum had wholly disappeared. All the plain of the Sarno was buried, as were also the slopes of the mountains on the south. Stabiae, as we have seen, lay at the foot of the mountains, on the coast. It had been destroyed by Sulla in the Social War; its inhabitants, forced to scatter, settled in the surrounding country. In the years 1749-82 numerous buildings were excavated in the vicinity, in part luxurious country seats, in part plain farm buildings; but the excavations were afterward filled up again. The covering of Stabiae was like that of Pompeii, only not so deep. Herculaneum was covered with the same materials; they were not, however, deposited in regular strata, but were mixed together, and being drenched with water, hardened into a kind of tufa which in places reaches a depth of sixty-five feet. Excavating at Herculaneum is in consequence extremely difficult; and the difficulty is further increased by the fact that a modern city, Resina, extends over the greater part of the ancient site. The excavations thus far attempted have in most cases been conducted by means of underground passageways. The statement that Herculaneum was overflowed by a stream of lava, though frequently repeated, is erroneous. [Illustration: Fig. 7.--Cast of a man.] The woodwork of buildings in Pompeii has in many cases been preserved, but in a completely charred condition. Frequently where walls were painted with yellow ochre it has turned red, especially when brought immediately into contact with the stratum of dust--a change which this color undergoes when it is exposed to heat. Nevertheless, the inference would be unwarranted that the products of the eruption fell upon the city red-hot and caused a general conflagration. The fragments of pumice stone could scarcely have retained a great degree of heat after having been so long in the air; it is evident from Pliny's narrative that they were not hot.