The fossil-bearing locality of Polazzo is a Lagerstätte dating to the Santonian (Late Cretaceous), about 85 million years ago. The site B (a site A excavated earlier occurs NNE), excavated every year since1996 (with a stop of one year for bureaucratical reasons), is situated on the SSE edge of the village of Polazzo. It consists of an outcrop of stratified limestone of limited extension belonging to the "calcari di Aurisina". The strike is 290°, the average dip is 24°. From a lithological and sedimentological point of view, it is made mainly of thinly-laminated limestone, usually of a light colour (grey or greenish), with a tabular geometry and sets that were disturbed post-deposition by tectonics. Micro-breccia levels are also present. The kind of fossils preserved and their state of conservation indicate the presence of an environment favourable to the fossilization of organic remains that are usually destroyed by the taphonomic processes. The excavated area covers about 50 square meters and its stratigraphic section is about 1 m thick. The section was divided into six main intervals (beds), and further divided into sub-intervals. The finds from the excavation total 1075 (in 2004). They comprise mainly skeletal remains of neopterygian bony fish mostly incomplete but very well preserved, and rarer plant remains (conifers). Among the Neopterygians, the Teleosts are dominant. Of particular importance are the specimens of the alepisauriform Rhynchodercetis (two specimens preserve their prey within their rib-cage), Beryciformes (basal Perciformes, of particular evolutionary interest), pycnodontiformes (basal Neopterygians), and several small teleosts possibly related to Cypriniformes. The tooth of a diapsid reptile, perhaps a small crocodyliform, was also found. All the specimens recovered are housed in the Museum in Via Valentinis, 134 at Monfalcone (Gorizia).

The excavation began on the 20th September 2009. In the initial phase activity mainly consisted in the extension of the work area (circa 4 m2) with the removal of detritus and of the soil covering the fossil-bearing layers. The extension of the excavation area became necessary because the limestone layers investigated in previous years resulted as being heavily disturbed by tectonics and the intrusion of tree roots. Furthermore, a basal compact level, extremely hard and without any important fossils, was reached in many points. Following the partial removal of the covering layers and the circumventing of the compact level reached during previous campaigns, work was undertaken on layers that were still rather disturbed by tectonics and showed numerous fractures cemented by calcite (layers D3, E1 and E2; Fig. 1). In this zone, the partial remains of only two fossil fish were found in layer E1. The disturbed layers terminated with a compact lithosome that was hard to work and not likely to contain fossils. Therefore, a zone beyond the compact lithosome was investigated, where the fissile and fossiliferous laminites reappeared. In this zone, excavation continued on an area of about one square metre until mid-December. It was also seen that laterally the solid lithosome seemed to become laminated and fissile. At present it is not possible to correlate the new laminate layers with the stratigraphic section excavated in previous years. Thus it was provisionally given separate numbering and initials (S). At the end of 2009 the total number of finds was 1175. The first part of the excavation produced five fossils (see attached list). These were the fragmentary remains of bony fish (Osteichthyes): two examples of the extinct genus _Rhynchodercetis_, a possible _Beryciformes_, a fragmentary teleost and a coprolite (fossil excrement), all from layer E1. In the second part of the excavation (new laminates) the remains of five bony fish were found, including a _Rhynchodercetis_ and a small, almost complete teleost (Cypriniform ?). Furthermore, a terrestrial plant was discovered (a leaf perhaps belonging to a dycotiledon). All the finds are temporarily housed in three containers in the palaeontological collections at the Gruppo Speleologico A.d.F.-Museo della Rocca, via Valentinis 134, a Monfalcone (Gorizia).

The excavation started on the 7th October 2011. Initially, work continued on the removal of the layers on the front opened in 2010. Unfortunately, after several days work, removing potential fossil-bearing layers, which produced no new finds, the underlying layers were reached. These were made up of compact non-fissile limestones. This trench was abandoned and back-filled. It was decided to open a new trench a few metres south of the area excavated between 1996 and 2010. The surface material of soil and rock fragments were removed in order to reach the underlying laminated layers. The partial removal of the first potentially fossil-bearing layers (Po1, Po2 and Po 3) began. So far they have only produced a few fragmentary remains of fish fossils and disarticulated and isolated skeletal elements – also of fish. The surface layers varied in colour between grey and light brown and were slightly undulated with vertically fractures. The upper part of layer Po1 mainly contained incomplete and disarticulated fossils and a few complete examples, covered by crystals and calcite. These were mostly the fragmentary remains of indeterminate teleostei fishes and pycnodontes, including two isolated scales (one large) and a vegetal specimen. There was a notable absence in these first layers of the Rhyncodercetis and small Beryciformes that were always present in layers excavated in previous years.

The fossil-bearing locality of Palazzo is a _ Lagerstätte_ datable to the Santonian period (Upper Cretaceous). Excavations on the site, situated on the edge of the village of Polazzo, began in 1996. The site is formed by an outcrop of calcareous layers of limited extension relating to the “calcari di Aurisina”. The attitude is 290°, the average direction of dip is 24°. From a lithological and sedimentological point of view, this type of limestone is generally densely laminated, usually light in colour (grey or tan), with tabular geometry and lamination that is sometimes disturbed (ripple marks) at the time of deposition, sometimes by tectonic movement. Also present are levels of micro-breccia. The particular association of fossils present and its state of preservation indicate the existence of a favourable environment for the fossilisation of organic remains, which are usually destroyed by taphonomic processes. The excavation area measured approximately 50 m2 and the stratigraphic section was about 100 cm deep. The section was divided into six main layers, then and divided into sub-layers. To date, 1235 finds have been recovered from the excavation. The fossils are represented by th skeletal remains, mostly incomplete, but very well-preserved, of bony fish (Osteichtheyes) Neopterygii and plants (conifers and dicotyledonae). The Teleostei are dominant among the Neopterygii. The finds included important examples of _Alepisauriforme Rhynchodercetis_ (inside two examples the prey was preserved), _Beryciformes_ (basal Percomorphs, of interest with regard to evolution), Pycnodontes (basal neopterygii), and numerous small teleostei of uncertain affinity (_Cypriniformes_ ?). Even a tooth from a crocodylomorph _notosuchus_ was found. This year’s excavation recovered 26 finds from layers 2, 3, and 4. All were from fish still largely covered with rock and therefore impossible to identify with any certainty, a part from the characteristic Pycnodontes (probably all of the _Polazzodus coronatus_ species) and some small _ Beryciformes_, and a large undetermined teleosteo. In 2012, a new sector was opened, as the characteristics of the rock in the sector investigated last year were not suitable for the fossilization of organisms and their discovery. The new sector was moderately fossil-bearing and to date an area of approximately 12 m2 and 40 cm in depth has been excavated. Not all the surfaces of the layers were fissile, as they had been heavily altered by root growth, karstification, and calcite intrusions, which had compromised their characteristics. However, there were some zones where the layers, in particular 2, 3, and 4, were well-preserved, although little fauna was present in them.

The 2014 excavations took place between the 28th September and 31st December in the sector investigated in 2013. Only seven days of actual excavating were managed due to the almost permanently rainy conditions. On wet days, it was not possible to work as the wet rock caused problems for the extraction of the finds and there was a risk of damage to the fossils. The site of Polazzo is constituted by a rock formation surrounded by “red earth” and the layers, on a 12/15° slope, become covered with a reddish patina when wet, which makes it difficult to identify the fossil remains. The work consisted in extracting and opening limestone slabs (using hammer and chisel) and then checking for the presence of fossils (that is, evidence of life from the geological past). If a fossil was found, the rock containing it was numbered and recorded, than carefully wrapped for transport to the storage facility. The palaeontological site of Polazzo preserves fossils dating to the Santonian-Coniacian chronostratigraphic interval of the Cretacean System (c. 85 million years ago according to the International Chronostratigraphic Chart of the IUGS, 2013). It includes a lithosome of limestone strata within a carbonate platform of the Upper Cretaceous period, partially disturbed by tectonics. This disturbance makes it difficult to identify the precise continuation of the fossil-bearing body. The particularity of the taphonomy preserved in the laminated limestone consists of the remains of articulated vertebrates (almost all examples of the bony fish Actinopterygii) and land plants in a perfect state of preservation. Therefore, the site can be considered a _Konservat-Lagerstaette_ (sensu Seilacher1970). As in 2013, the work was undertaken on a surface of c. 15 m2 with an average depth of stratigraphy of about 60 cm, divided into four strata numbered from 1 (upper) to 4 (lower). The 2014 _sondage_ mainly concentrated on strata 3 and 4 and, as in the previous year, the layers were not always suitable for finding and extracting fossils, due to local alterations produced by plant roots (which grow into the cracks in the rock), karstification and presence of calcitic intrusions (linked to the tectonic disturbance). However, some zones in the excavation area presented optimum conditions for the separation of the fissile limestone but, unfortunately, they contained few fossils and the finds consisted only of fish fragments. A total of eight finds were recovered, from strata 2 (one find), 3 (two finds) and 4 (five finds) (see table 1). These were fragments of fish, still mainly unidentified. The skeletal remains were often still partially covered by a lamina of rock that, obviously, made certain systematic identification impossible without adequate preparation; probably they are mainly – but not exclusively – Teleostei and it is possible to hypothesise a more precise identification for some examples. One (2/2014) was a Pycnodontiformes (a clade of semi-durophagous fish that was widespread in tropical seas during the Cretaceous era) and another find (5/2014) belonged to the _Rhynchodercetis_ genus (a predatory fish with a slender body that only lived during the Upper Cretaceous era), both already known on the site. Further information on the systematic determination of the finds will only be obtained after they have been prepared and their study is completed.