A river overflowing recovers these first testimonies with a thick, lacustral blanket of silt. Above the silt, the prehistoric people return to settle, leaving other traces of their passage.
This time the land is recovered by a volcanic mudslide, sealing the precious finds and preserve them from the destruction. The sanidine and biotite crystals present in these volcanic sediments can be dated to 736,000 +/- 40,000 years ago according to the Potassio/Argon method. The prehistoric people return for the third time in the area, settling above the volcanic sediments, leaving numerous lithic handiworks, obtained from flint-stone, limestone and little osteological remains. Once again the testimonies are sealed because of a new, fluvial sediments accumulation.
The fourth phase of the zone peopling is documented in the Southerner area of the layer and is characterised of a very strong concentration of handiworks, obtained exclusively from flint-stone and poor osteological remains of little dimensions. This last group of testimonies is particularly interesting, either for the probable presence of fire-utilization traces (until now, the eldest one documented in the world) and for the exceptional reliability of the finds attitude conditions, which don’t show any phenomenon of “post-depositional” trouble: they have a very fresh aspect, strongly concentrating in a defined area and often reassembling each other.
Establishing precisely the interval passing among the four different phases of the Paleolithic peopling of the zone is not easy: the sediments characteristics interposing there, which can be accumulated also in very fast times, the constant presence of the same kinds of faunas and the strong analogies characterising the four groups of lithic handiworks, let us think that these times were particularly short (which could mean from some months to some centuries).

Source: L’ITINERANTE Isernia Camper Club Magazine N. 9