Nummulite

A calcareous, thin-pore-impregnated shell, spirally symmetrically curled and shaped like a rounded plate or biconvex (less often to spherical); the number of revolutions is very large, the height, as well as their width increases very gradually; the number of chambers is very large, the last revolutions are mostly closed in the form of a ring surrounding the entire shell (the transition from the spiral arrangement of the chambers to the circular one), the last revolutions completely enclose the previous ones, the hole is simple, the system of channels in the walls of the sink and its partitions is very well developed. In the subgenus Numullina, the cavities of the chambers continue along the sides to the shell axis, and only the last turn of it is usually visible from the outside; the partitions are radial, in various ways curved or crimped, sometimes branched and dividing the sides of the chambers into small chambers; this includes only one modern look and a number of minerals. They are close to nummulites and belong to the same family (Nummulitinae) and subfamily (Nummulitidae) from the genera Polystomella , Operculina , Cyclammina , which also have modern representatives.

Characteristic of the Eocene sediments of the oceanic type. These include large calves, calcareous, circular or lenticular, ranging in size from the size of a pinhead to a silver ruble. The shell is composed of many spiral-increasing turns, divided by transverse partitions into numerous interconnected chambers. Nummulites appear already in the Carboniferous system and exist to this day, but the greatest development reached in the age of the Eocene . Shucks nummulites overwhelmed sometimes huge column nummulitovyh limestone widely distributed over the earth's surface to reveal even the snowy peaks of the Pyrenees , the Alps , the Carpathians and the Himalayas , certainly suggesting that in comparatively recent geological times, these mountains did not exist, and in their place was overflowing huge Eocene ocean , at the bottom of which myriad buried nummulites and other organisms modern to them.

• In fact, the main material used in the construction of the famous Egyptian pyramids was nummulite limestone. Ancient Greek historian Herodot in the V century BC drew attention to the presence of some remains of shells in the materials of construction of the pyramids.
• Greek historian and geographer Strabo in the 1st c. BC er re-fixes and describes the organic remains already seen by Herodotus in the pyramids, but assumes that these are the remains of petrified lentils that the ancient builders ate.
• In Europe, the remains of nummulites (apparently) were found in the vicinity of Paris, as described by Agricola and Conrad Gesner , the latter of whom considered the finds to be one of the types of ammonites .
• Under the name Lapides numismales Transylvanie, the sixteenth century French botanist Carl Clusius wrote about them.
• The genus was first proposed by Lamarck in his work The System of Invertebrates in 1801. Lamarck identified the nummulites as the 89th genus of cephalopod mollusks between planulites and spiruli .
• In 1825, d'Orbigny singled out the Foraminifera detachment as part of cephalopods, to which nummulites belonged.
• In 1835, Felix Dujardin singled out a group of Rhizopods (rooted-knit knots) , which also included nummulites. Later, the rhizopods were classified as protozoa and protists .

According to the World Register of Marine Species , as of July 2016, the genus includes 6 species, 2 of which became extinct ^[1] :

• Nummulites barroni Chapman, 1900
• † Nummulites gizehensis (Forsskål, 1775 in Niebuhr, 1775)
• Nummulites hyalinus Hofker, 1956
• † Nummulites laevigata (Bruguiere, 1792)
• Nummulites lenticulus Blainville, 1825
• Nummulites niasi Verbeek, 1896

• Nummulite // Encyclopedic Dictionary of Brockhaus and Efron : 86 t. (82 t. And 4 extra.). - SPb. , 1890-1907.
• Introduction to the Study of the Foraminifera by William Benjamin Carpenter

• Hayward, B. (2014). Nummulites Lamarck, 1801. In: Hayward, BW, Cedhagen, T., Kaminski, M., Gross, O. (2014) World Foraminifera Database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=520941 on 2014-11-13
• Nummulite (TSB) (inaccessible link)
• 'Nummulite', Tiscali Dictionary of Animals [1] , retrieved 17 August 2004
• 'Biggest Microbes', Guinness World Records 2001 , p. 153.
• Illustrated glossary of terms used in foraminiferal research