Monte Bolca is an
Early Eocene
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...
-aged geologic site located near
Verona
Verona ( ; ; or ) is a city on the Adige, River Adige in Veneto, Italy, with 255,131 inhabitants. It is one of the seven provincial capitals of the region, and is the largest city Comune, municipality in the region and in Northeast Italy, nor ...
,
Italy
Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...
. A ''
Konservat-Lagerstätte'', it contains an extremely well-preserved and diverse marine biota, including the most diverse fish fauna of any Cenozoic fossil site, as well as many of the earliest fossil occurrences of modern marine fish groups. It was one of the first fossil sites with high quality preservation known to Europeans, with studies of its biota dating back to the 18th century and earlier, and is still an important source of fossils.
History
Strictly speaking, the Monte Bolca site is one specific spot near the village of Bolca in Italy, known as the ''Pesciara'' ("The Fishbowl") due to its many extraordinarily well preserved
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
fish fossils. However, there are several other related outcroppings in the general vicinity that also carry similar fossils, such as Monte Postale and Monte Vegroni. The term Monte Bolca is used interchangeably to refer to the one, original site, or to all the sites collectively.
The fossils at Monte Bolca have been known since at least the 16th century,
though the first extensive research was conducted on them by
Giovanni Serafino Volta
Giovanni Serafino Volta (1764–1842) was an Italian priest, naturalist, and palaeontologist, best known for his studies of fossil fish from Monte Bolca.
Volta was an ''Abate'' (or abbot) and theologian. He was a Canon of the Imperial Basilica i ...
in the late 18th century.
They were studied intensively in the 19th century once it was definitively proven that fossils were the remnants of dead animals.
Fossils from Monte Bolca are commonly available for sale by commercial fossil dealers, and due to their popularity and preservation regularly sell for several hundred dollars.
Geology
All sites referred to as being a part of Monte Bolca are located in the eastern part of Monti Lessini near Verona, northern Italy. This area represents a continuation of the
Southern Alps
The Southern Alps (; officially Southern Alps / Kā Tiritiri o te Moana) are a mountain range extending along much of the length of New Zealand, New Zealand's South Island, reaching its greatest elevations near the range's western side. The n ...
. Though all of these sites have been put under a single name, there is not a place called "Monte Bolca". Due to the differences in the environment and stratigraphy, more recent authors have also called these sites the Bolca Lagerstätten.
Due to volcanic events that had taken place in the area, a number of tectonic disturbances are present which were a result of the uplift of the ‘‘Trento Plateau’’. The nonuniform uplift of this plateau also caused the creation of the Lessini Shelf which was the northernmost margin of the
Adriatic Plate
The Adriatic or Apulian plate is a small list of tectonic plates, tectonic plate carrying primarily continental crust that broke away from the African plate along a large transform fault in the Cretaceous period. The name Adriatic plate is usu ...
. Multiple authors have mentioned a sub-vertical fault that runs north northwest-south southeast just west of Bolca. However, more recent work done at Monte Postale has not seen the presence of this supposed fault and has since been discarded.
Spilecco
Spilecco, also known as Spilecco Hill, is largely made up of poorly-exposed reddish marly and grey-green
limestones
Limestone is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Limestone forms when these ...
. While the fossil content of the grey-green limestones is made up of various microfossils, macrofossils are found in the reddish marly limestones. The strata within Spilecco date from the Thanetian to lower Ypresian which make them the oldest shallow water deposits in the Lessini Shelf and would have been deposited after the first period of volcanic activity.
[The Bolca Fossil-Lagerstätten: A window into the Eocene World]
Pesciara
The Pesciara site of Monte Bolca is made up of a sheet-like limestone in the form of an olistolith which has an area of a few hundred square meters and is under 20 m thick. Throughout this bed, there are both reef and alveoline limestones which are medium-fine grained. The different limestone beds alternate between the fossiliferous laminites and more course-grained biocalcarenites and biocalcirudites. These more course layers are a lot less fossiliferous though still contain fossils such as foraminifera and mollusks. Most fossils within the Persciara site have been found within five of the levels with the 1st, 2nd, and 5th levels being the most productive. However, due to being completely excavated over the last four centuries, the 5th level is no longer accessible.
Towards the south-east of the deposit, the limestone layers dip at a 24° angle which suggests that the beds slid towards the north-west when they were more plastic. Volcanoclastic rock surrounds the limestone beds and due to this isolation, there has been trouble in understanding the relationship between the Pesciara and Monte Postale sites.
Due to the foraminifera and other fossils found at the site, Pesciara has been assigned to the late Ypresian.
Monte Postale
The Monte Postale site of Monte Bolca is located north of Pesciara and represents a succession with a thickness of over 130 m. Throughout this complex succession, there are transitions from fine-grained limestones to massive coralgal limestones.
These coralgal limestones are highly abundant in coral colonies and range from weakly to massive stratification. The thicker logs of the coralgal limestones are about 13.7 m in thickness each with the finer-grained logs being thinner. Within all of these logs, there is ''Alveolina'' present however it is much more common in the coarser-grained sediments.
Though the site is largely known for the fish and plants found, Monte Postale is also well known for the molluscan fauna located at the uppermost section of the site. Just like Pesciara, the stata of Monte Postale have been dated to the late Ypresian with the upper-most portion of the beds being potentially correlated to the limestones seen at Pesciara.
Purga di Bolca and Vegroni
Unlike Pesciara and Monte Postale, Purga di Bolca and Vegroni are representative of freshwater to brackish environments. Both localities are within a volcanic cone whose base has been dated to the Ypresian, similar to the other sites of Monte Bolca. Purga di Bolca is made up of silts, clays, and lignites with contain the vertebrates and mollusks of these localities. This locality is preserved as a conical hill and ranges between 10-20 m in thickness. Under these strata there are tuffaceous layers containing palms. The succession between the two is interrupted by layers of basalt. Though the base of the cone date to a similar age to the other sites, this more terrestrial environment is younger than the above mentioned marine strata. The palm beds found in the Vegroni locality have been dated to the early Oligocene while the basaltic layer have been dated to the Bartonian.
The correlation between these more terrestrial and marine faunas have long been problematic.
Species in the formation
Animal fossils

Monte Bolca is rich in fish: 250 species (140 genera, 90 families and 19 orders).
[Williams, Matt]
Fauna and Flora of Monte Bolca
, University of Bristol Additionally a cephalopod, crustaceans, jellyfish and polychaete worms have been found whole, but foraminifera, molluscs, and corals are found in fragments and may have been transported.
Bird feathers and tortoise shell plates have been found, as well as many insects, freshwater and land plants.
Notable fossil species include:
*
Fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
** ''
Angiolinia mirabilis'', an
zanclid fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
** ''
Bolcaperca craccorum'', an
perch
Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...
** ''
Blochius
''Blochius'' is an extinct genus of billfish from the Eocene. It is only known from the Monte Bolca deposits in Italy, and was likely restricted to shallow, tropical waters of the Tethys Ocean.
Discovery
The existence of ''Blochius'' was known ...
longirostris'', an
ancestral swordfish
** ''
Ceratoichthys
''Ceratoichthys'' is an extinct genus of lookdown-like prehistoric jackfish that lived during the late Ypresian epoch, of the Early Eocene. It contains a single species, ''C. pinnatiformis'' of Monte Bolca, Italy. It and '' Vomeropsis'' are the ...
'', an unusual
jack fish
** ''
Bolcaichthys'', a
herring
Herring are various species of forage fish, belonging to the Order (biology), order Clupeiformes.
Herring often move in large Shoaling and schooling, schools around fishing banks and near the coast, found particularly in shallow, temperate wate ...
relative and the most abundant fish of the formation
** ''
Cyclopoma gigas'', a large
percomorph
Percomorpha () is an extremely large and diverse clade of ray-finned fish. With more than 17,000 known species (including Scombroidei, tuna, Syngnathiformes, seahorses, gobies, Cichlidae, cichlids, flatfish, Labridae, wrasse, Perciformes, perches ...
** ''
Eastmanalepes primaevus'', a jack fish
** ''
Eolactoria sorbinii
''Eolactoria'' ("dawn '' Lactoria''") is an extinct genus of highly unusual prehistoric boxfish from the Eocene. It contains a single species, ''E. sorbinii'' from the Ypresian-aged Monte Bolca site in Italy.
It had two pairs of long spines, ...
'', a
boxfish
Ostraciidae or Ostraciontidae is a family of squared, Actinopterygii, bony fish belonging to the order Tetraodontiformes, closely related to the pufferfishes and filefishes. Fish in the family are known variously as boxfishes, cofferfishes, cowfi ...
** ''
Eoplatax
''Eoplatax'' ("dawn ''Platax''") is an extinct genus of prehistoric Ephippidae, spadefish that lived during the Early Eocene. It contains a single species, ''E. papilio'' (=''E. subvespertilio'' (Henri Marie Ducrotay de Blainville, de Blainville, ...
papilio'', a
batfish
** ''
Exellia velifer'', a
spadefish
Ephippidae is a family of percomorph fishes, the spadefishes, in the order Moroniformes. These fishes are found in the tropical and temperate oceans of the world, except for the central Pacific.
Taxonomy
Ephippidae was first proposed as a famil ...
** ''
Godsilia lanceolata'', a primitive
tuna
A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...
** ''
Eolates
''Eolates'' ("dawn ''Lates''") is an extinct genus of prehistoric lates perch from the Paleogene of Europe. It contains three species, two marine and one freshwater, known from the early-middle Eocene and Chattian, Late Oligocene.
The following ...
'', a
relative
Relative may refer to:
General use
*Kinship and family, the principle binding the most basic social units of society. If two people are connected by circumstances of birth, they are said to be ''relatives''.
Philosophy
*Relativism, the concept t ...
of the
Nile perch
The Nile perch (''Lates niloticus''), also known as the African snook, Goliath perch, African barramundi, Goliath barramundi, Giant lates or the Victoria perch, is a species of freshwater fish in family Latidae of order Perciformes. It is wides ...
** ''
Caruso brachysomus'', a primitive
anglerfish
The anglerfish are ray-finned fish in the order Lophiiformes (). Both the order's common name, common and scientific name comes from the characteristic mode of predation, in which a modified dorsal Fish fin#Ray-fins, fin ray acts as a Aggressiv ...
** ''
Mene rhombea'' and ''
Mene oblonga'', early
moonfish
** ''
Paranguilla tigrina'', an
eel
Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...
with preserved coloration
** ''
Pasaichthys pleuronectiformis'', a
mooneyfish
** ''
Platax altissimus'' and ''Platax macropterygius'',
spadefish
Ephippidae is a family of percomorph fishes, the spadefishes, in the order Moroniformes. These fishes are found in the tropical and temperate oceans of the world, except for the central Pacific.
Taxonomy
Ephippidae was first proposed as a famil ...
** ''
Platinx'', one of the last
crossognathiform fish
** ''
Proaracana dubia'', an
aracanid boxfish
** ''
Protobalistum imperial'', a relative of boxfish and triggerfish
** ''
Psettopsis subarcuatus'', a mooneyfish
** ''
Pycnodus
''Pycnodus'' (from , 'dense' and 'tooth') is an extinct genus of Actinopterygii, ray-finned fish from the Eocene period. It is a wastebasket taxon, although many fossils from the Jurassic or Cretaceous are assigned to this genus, only the Eoce ...
platessus'', one of the last
pycnodont
Pycnodontiformes is an extinct order of primarily marine bony fish. The group first appeared during the Late Triassic and disappeared during the Eocene. The group has been found in rock formations in Africa, Asia, Europe, North and South America. ...
fish
** ''
Pygaeus nobilis'', a bony-fish
** ''
Serranus
''Serranus'' is a genus of fish in the family (biology), family Serranidae. It is one of five genera known commonly as the "Atlantic dwarf sea basses". These fish are hermaphrodites, each individual possessing functional male and female reproduct ...
occipitalis'', a
sea bass
Sea bass is a common name for a variety of species of marine fish. Many fish species of various families have been called sea bass.
In Ireland and the United Kingdom, the fish sold and consumed as sea bass is exclusively the European bass, ''Dic ...
** ''
Sharfia mirabilis
''Sharfia mirabilis'' is an extinct species of anglerfish in the family Lophiidae. It was discovered in 2011 during a review of fossil material at the Muséum national d'histoire naturelle in Paris. The fossil material was collected from the M ...
'', an anglerfish
** ''
Sphyraena bolcensis
''Sphyraena bolcensis'' is an extinct species of prehistoric barracuda known from the Eocene. It is known from the late Ypresian-aged Monte Bolca site of Italy.
Taxonomy
It is one of the earliest and best-known fossil barracudas. It was initia ...
'', one of the earliest
barracudas
** ''
Spinacanthus cuneiformis'', a
relative
Relative may refer to:
General use
*Kinship and family, the principle binding the most basic social units of society. If two people are connected by circumstances of birth, they are said to be ''relatives''.
Philosophy
*Relativism, the concept t ...
of boxfish and
triggerfish
Triggerfish are about 40 species of often brightly colored marine ray-finned fishes belonging to the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest speci ...
** ''
Zorzinichthys'', a zorzinichthyid percomorph
*
Sharks
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...
** ''
Galeorhinus cuvieri'', a relative of the modern
school shark
The school shark (''Galeorhinus galeus'') is a houndshark of the family Triakidae, and the only living member of the genus '' Galeorhinus''. Common names also include tope, tope shark, snapper shark, and soupfin shark. It is found worldwide in t ...
** ''
Eogaleus'', an early
requiem shark
Requiem sharks are sharks of the family Carcharhinidae in the order Carcharhiniformes. They are migratory, live-bearing sharks of warm seas (sometimes of brackish or fresh water) and include such species as the bull shark, lemon shark, blac ...
** ''
Brachycarcharias'', a
sand shark
*
Rays
Ray or RAY may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), the bony or horny spine on ray-finned fish
Science and mathematics
* Half-line (geometry) or ray, half of a line split at an ...
** ''
Arechia crassicaudata'', an
stingaree
The Stingaree was a neighborhood in downtown San Diego from the boom of the 1880s until it was demolished during a vice eradication campaign of 1916. It was the site of the city's Chinatown.Elizabeth Perl (Spring, 1977). San Diego's Chinese Mis ...
** ''
Dasyomyliobatis'', a
stingray
Stingrays are a group of sea Batoidea, rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae (sixgill stingray), Plesiobatidae (deepwate ...
intermediate between
whiptail stingrays and
eagle rays
The eagle rays are a group of cartilaginous fishes in the family Myliobatidae, consisting mostly of large species living in the open ocean rather than on the sea bottom.
Eagle rays feed on mollusks, and crustaceans, crushing their shells with th ...
** ''
Lessiniabatis'', a bizarre stingray with a highly reduced tail
*
Lobster
Lobsters are Malacostraca, malacostracans Decapoda, decapod crustaceans of the family (biology), family Nephropidae or its Synonym (taxonomy), synonym Homaridae. They have long bodies with muscular tails and live in crevices or burrows on th ...
**''
Justitia
Lady Justice () is an Allegory, allegorical personification of the moral force in judicial systems. Her attributes are Weighing scale, scales, a sword and sometimes a blindfold. She often appears as a pair with Prudentia.
Lady Justice originat ...
desmaresti''
*
Crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large, semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term "crocodile" is sometimes used more loosely to include ...
**''
Crocodilus vicetinus''
*
Snakes
Snakes are elongated Limbless vertebrate, limbless reptiles of the suborder Serpentes (). Cladistically Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales much like other members of ...
** ''
Archaeophis
''Archaeophis proavus'' is an extinct species of marine palaeophiid snake from the Eocene of Monte Bolca, Italy. It had the highest vertebral count known among snakes, with 565 vertebrae.
Massalongo also described a second species in the genu ...
bolcaensis''
** ''Archaeophis proavus''
*
Cephalopods
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
** ''
Bolcaoctopus pesciaraensis'', an
octopus
An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like oth ...
Plant fossils
One of the more interesting puzzles in ichnotaxonomy, pertains to fossils from Monte Bolca, originally named ''
Zoophycos caput-medusae'', previously thought to be
trace fossil
A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...
s, were found to be plants instead and given the name
Algarum by French zoologist
Henri Milne-Edwards
Henri Milne-Edwards (23 October 1800 – 29 July 1885) was a French zoologist.
Biography
Henri Milne-Edwards was the 27th child of William Edwards, an English planter and colonel of the militia in Jamaica and Elisabeth Vaux, a Frenchwoman. Hen ...
in 1866.
The type specimen collected by Italian
paleobotanist
Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments (pale ...
Abramo Bartolommeo Massalongo
Abramo Bartolommeo Massalongo (13 May 1824 – 25 May 1860) was an Italian paleobotanist and lichenologist. He was born in Tregnago in the Province of Verona and took a great interest in botany as a young man. Massalongo joined the faculty of med ...
before 1855 is at the Natural History Museum of
Verona
Verona ( ; ; or ) is a city on the Adige, River Adige in Veneto, Italy, with 255,131 inhabitants. It is one of the seven provincial capitals of the region, and is the largest city Comune, municipality in the region and in Northeast Italy, nor ...
and was preserved in a
lithographic limestone
Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect-free to be used for lithography.
Geologists use the term "lithographic texture" to refer to a grain size under 1/250 mm.
The term "sublitho ...
upper and lower slab.
When Italian
botanist
Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...
Achille Forti (28 November 1878 Verona -11 February 1937 Verona) worked on the specimens in 1926, they were reinterpreted as close relatives of the sea palm, now known to be a
brown algae
Brown algae (: alga) are a large group of multicellular algae comprising the class (biology), class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate ...
, which had lived in the
coastal waters
A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...
of the Eocene sea.
He renamed the species ''Postelsia caput-medusae'' which makes it related to the genus ''
Postelsia
''Postelsia palmaeformis'', also known as the sea palm (not to be confused with the southern sea palm) or palm seaweed, is a species of kelp and classified within brown algae. It is the only known species in the genus ''Postelsia''. The sea pa ...
'', now with only one living species, which was described by its discoverer
Franz Josef Ruprecht
Franz Josef Ruprecht (1 November 1814 – 4 April 1870) was an Austrian-born physician and botanist active in the Russian Empire, where he was known as Frants Ivanovič Ruprekht ().
Life
He was born in Freiburg im Breisgau, and grew up in Prague ...
in 1852 as ''Postelsia palmaeformis''.
His type-specimen is from
Bodega Bay, California
Bodega Bay is a village and census-designated place (CDP) in Sonoma County, California, Sonoma County, California, United States. The population was 912 at the 2020 census. The town, located along California State Route 1, State Route 1, is on ...
,
but the species is found along the Pacific coast. The appearance of the plant is a holdfast on the bottom, with a stem-like stipe between there and the fronds which are about to .
In life, the fronds hang vertically when the tide is in but flop over the stipe when exposed by low tide.
Curiously, other specimens from this deposit collected and described by Massalongo in 1855 were actually trace fossils, only this one was a plant.
See also
*
List of fossil sites
This list of fossil sites is a worldwide list of localities known well for the presence of fossils. Some entries in this list are notable for a single, unique find, while others are notable for the large number of fossils found there. Many of ...
''(with link directory)''
References
{{commons category, Monte Bolca
External links
PDF Les fossiles de Bolca- Fossils of Bolca - I fossili di Bolca
PDF Fishes from the Eocene of Bolca Bannikov, Alexandre, Geodiversitas 28 (2): 249-275
Paleontological sites of Europe
Eocene Europe
Lagerstätten
Paleogene Italy
Paleontology in Italy
Archaeological sites in Veneto
Geography of Veneto
History of Veneto
Ypresian Stage
Shallow marine deposits