belemnites
Belemnites
The name of the belemnite derives from the name belemnon, Greek, meaning dart. The fossilized part of the belemnite is usually the guard, the back part of the shell, which does look like a bullet or dart. The belemnite is similar to a modern day squid, however, squids have suckers on their arms rather than the belemnite which had hooks for grabbing their prey.
Belemnites disappeared during the Cretaceous-Tertiary extinction event. This is during the time that dinosaurs and ammonites became extinct too. They are the most commonly known fossil after ammonites. They are a very characteristic and easily recognisable fossil usually resembling a bullet in shape, although this only represents the extreme 'tail' of the animal (Phil Eyden 2003).
Names for the Belemnite around the world:
“In England, they were called thunderbolts, and they were supposed to fall from the sky during thunderstorms. They were also called bullets, Devil's Fingers or Saint Peter's Fingers.
In Scotland, they were known as botstones or bat stones. They were used to cure horses.
In Chinese, belemnites are known as Jien-shih (sword stones).
In some areas of Scandinavian, they are called vateljus (gnomes' candles).
In Germany, they are known as Alpschoß (nightmare shot), Fingerstein (finger stone), Gespensterkerze (ghostly candle) and Katzenkegel (cat's skittle). “ (Jo Edkins 2007).
The Guard
The belemnite guard can be described as being bullet shaped and, indeed, these fossils were commonly called ‘bullet stones’ in times past. This part of the creature, located furthest from its head, was composed of calcite and tapered to a point at the extremity. At the end closest to the head the guard was indented by a conical cavity called the alveolus. Within this was found the base of the phragmacone.
It is thought that the guard acted as a counterweight to the phragmacone. Guard fossils are nearly always composed of calcite.
The Phragmacone
The phragmacone extended out of the guard. It was a conical structure, divided up by simple, concave sutures and was used to regulate the animal’s buoyancy. This part of the belemnite is less commonly found as fossils than the guard due to its more fragile nature. When found, however, it may be preserved in a variety of different rock or mineral types, such as mudstone, pyrite or calcite, and may be inflated as in life or crushed flat. Sometimes the phragmacone and guard fossils can be found still attached to each other.
From the wide end of the phragmacone extended a thin, paper-like structure called the pro-ostracum. This is only very rarely found fossilised.
(x)
References
Edkins, Jo (2007) Belemnites [Online] Available from: http://gwydir.demon.co.uk/jo/fossils/belemnite.htm [Accessed 08 March 2016]
Eyden, Phil (2003) Belemnites: A Quick Look [Online] Available from: https://www.tonmo.com/pages/belemnites/ [Accessed 08 March 2016]
The name of the belemnite derives from the name belemnon, Greek, meaning dart. The fossilized part of the belemnite is usually the guard, the back part of the shell, which does look like a bullet or dart. The belemnite is similar to a modern day squid, however, squids have suckers on their arms rather than the belemnite which had hooks for grabbing their prey.
Belemnites disappeared during the Cretaceous-Tertiary extinction event. This is during the time that dinosaurs and ammonites became extinct too. They are the most commonly known fossil after ammonites. They are a very characteristic and easily recognisable fossil usually resembling a bullet in shape, although this only represents the extreme 'tail' of the animal (Phil Eyden 2003).
Names for the Belemnite around the world:
“In England, they were called thunderbolts, and they were supposed to fall from the sky during thunderstorms. They were also called bullets, Devil's Fingers or Saint Peter's Fingers.
In Scotland, they were known as botstones or bat stones. They were used to cure horses.
In Chinese, belemnites are known as Jien-shih (sword stones).
In some areas of Scandinavian, they are called vateljus (gnomes' candles).
In Germany, they are known as Alpschoß (nightmare shot), Fingerstein (finger stone), Gespensterkerze (ghostly candle) and Katzenkegel (cat's skittle). “ (Jo Edkins 2007).
The Guard
The belemnite guard can be described as being bullet shaped and, indeed, these fossils were commonly called ‘bullet stones’ in times past. This part of the creature, located furthest from its head, was composed of calcite and tapered to a point at the extremity. At the end closest to the head the guard was indented by a conical cavity called the alveolus. Within this was found the base of the phragmacone.
It is thought that the guard acted as a counterweight to the phragmacone. Guard fossils are nearly always composed of calcite.
The Phragmacone
The phragmacone extended out of the guard. It was a conical structure, divided up by simple, concave sutures and was used to regulate the animal’s buoyancy. This part of the belemnite is less commonly found as fossils than the guard due to its more fragile nature. When found, however, it may be preserved in a variety of different rock or mineral types, such as mudstone, pyrite or calcite, and may be inflated as in life or crushed flat. Sometimes the phragmacone and guard fossils can be found still attached to each other.
From the wide end of the phragmacone extended a thin, paper-like structure called the pro-ostracum. This is only very rarely found fossilised.
(x)
References
Edkins, Jo (2007) Belemnites [Online] Available from: http://gwydir.demon.co.uk/jo/fossils/belemnite.htm [Accessed 08 March 2016]
Eyden, Phil (2003) Belemnites: A Quick Look [Online] Available from: https://www.tonmo.com/pages/belemnites/ [Accessed 08 March 2016]