The excavation area is situated on the left side of a small valley leading off from the right side of the Valle della Mola. It lies within the municipality of Roncà in the locality of Costo, at about 205 m a.s.l.

The research programmed for 2010 aimed to trace, through stratigraphic excavation, the important deposit of molluscs and marine mammals of the Bartonian period (middle-upper Eocene), known as the “Roncà horizon”.

The paleontological excavation proper was preceded by a series of test pits, within the area identified previously, in order to identify the fossiliferous deposit with greater precision.
The first excavation campaign was undertaken between 15th-20th November, involving a number of fronts varying between about 2 and 15 m in length and 1 to 3 m in depth.

Initially area A was cleaned by the removal of soils and other surface detritus. At the end of the first day, given the impossibility of reaching the Roncà horizon due to the depth of the detritus and risk of collapse from the rock wall above, it was decided to interrupt work in area A and to continue with surface investigations which gave good results. By the basalt cascade/waterfall (area B), along the nature trail and to the side of the lay-by, there was an outcropping of a calcareous-cinereous horizon rich in nummulites and gastropods (Campanile, Velates, etc.), often of large dimensions. Therefore, two main excavation areas were identified: area A (situated uphill from the country road/track) and Area B (by the waterfall).

Area A

Deposit of fine and incoherent sediment, alternating with basalt blocks derived from processes of fracturing and gravitational accumulation. Bioclasts (mainly gastropods and bivalves) were found in the loose sediment and, due to washing away, in the hill deposit below. The bioclasts (of centrimetrical dimensions) were well-preserved (presence of shell and ornamentation) and did not present deformations. This indicates a low-energy sedimentary environment and a weak lithostatic load during the phase of diagenisis.

Area B

Two layers were identified.
Layer 1: silty limestone with occasional bioclasts and fragments of yellowish organic (plant) remains. Heavily fractured. Thickness >60 cm. Gradually transition into layer 2 through intercalations of clayey levels.
In areas A and B rock samples were taken for thin-section analysis. A preliminary analysis of the paleontological content showed that almost all of the finds were molluscs (gastropods and bivalves) and Foraminifers (Nummulites brongniarti).

A dental plaque, plant remains, echinoderms and crustaceans were also found. Overall 571 paleontological finds were recovered from the excavation in the locality of Valles della Chiesa.