The stratigraphy is formed by Latin stratum and Greek graphia is the study of rock succession and correlation of geological events and processes in time and space. This is the fundamental for all geological studies and reconstructing the events of Earth's history and evolution of life on Earth.
Stratigraphy knowledge is as old as philosophy which was originated by the ancients of Earth's natural phenomena and their philosophies on the nature of Earth's structure and processes. Different views were adopted among various ancient civilizations.
The ancient Greeks and Romans
The early observations were made by Ionian philosophers contributed mostly and to them the Earth's structure and processes were natural phenomena and not the supernatural causes. The term 'Fossil' comes from the Latin fossilis means anything dug from the Earth. Originally fossil was not used for living organism as we speak of today but for rocks, crystals anything that comes from Earth. At those early times there were two hypotheses generated for fossils. According to Greek philosopher Aristotle (384-322 B.C.), he said that some natural forces makes shape of living organism from inorganic material that are preserved in the rocks. The organic view of the fossils was that they are remains of once living organism that are preserved and this idea was given even before Aristotle. In 6th and 5th Centure B.C. both Pythagoras (582-507 B.C.) and Herodotus (484-425 B.C.) mentioned marine shells found on the mountain and on land places which were far from sea, argued this to be the remain of living organism which once were in sea later withdrew and became land. Herodotus thought that the disc shaped nummulitid foraminifera found in the Eocene limestone of which the Egyptian pyramids are built were lentils given to the slaves to fed who were building the pyramids and accidentally spilled and turned into stone. The Greek Xenophanes of Colophon, Ionia (570-480 B.C.), a pre-Socratic Greek philosopher and Pythagorean reported the occurrence of marine shells on top of mountains and quarries. For them it was the proof that Earth keeps changing with time and the remains of extant forms were buried in the dried sea.
The Romans gave more practical scientific accomplishments of the Greeks. Pliny the elder (23-79 A.D.) was a Roman naturalist and encyclopedist who was killed by eruption on 23-25 August 79 A.D. wrote a major encyclopedia of natural sciences which included 37 volumes and contained a summary of ancient knowledge on the nature of physical universe, a work mostly swimming up what the ancient Greek authors have written. In the early centuries after Christ the idea of organic origin was accepted and spread out. By the fall of Roman Empire in the 5th Century the knowledge was passed out to Muslims. All of the Greek work was translated into Arabic and then further added to them.
The Principles of stratigraphy
During the middle ages and the Renaissance, the Aristotelian school, through a Muslim, the Persian philosopher and physician Ibn-e-Sina (Avicenna, 980-1037), influenced many European scholars who attributed the occurence of fossils to failed abortive attempts of a natural creative 'plastic force' to shape living organism in a process of spontaneous generation of life. The scientist, philosopher and thelogian (1206-1280), born at Lauingen, Swabia, and later Leonardo da Vinci (1425-1519), were the first to correctly speculate on the nature of fossils as the remain of once living ancient organisms. The Leicester Code is a collection of numerous manuscripts with handwritten notes of Leonardo's scientific and technical observations. Among them there are drawings of rock formations and of various fossil shells (mostly Cenozoic mollusks), which are probably recollections of his experiences and observations on the hills of Tuscany, Romagna or the Po River plain, during his service as an engineer and artist at the court of Lodovico Sforza, Duke of Milan, from 1482 to 1499. From his notes Leonardo appears to have noticed the mechanisms of sedimentary deposition on mountains and rivers, the role that rivers play in the erosion of land and the principles of the law of superposition, which would later be demonstrated fully by Nicholaus Steno in 1669. He also appear to have grasped that distinct layers of rocks and fossils could be traced over long distances, and that these layers were formed at different times. After Leonardo's death his notes were scattered to libraries and collections all over Europe. While portions of Leonardo's technical treatises on painting were published as early as 1651, the scope and caliber of much of his scientific work remained unknown until the 19th Century. Yet his geological and paleontological observations and theories foreshadow many later breakthroughs. Nearly three hundred years later, the rediscovery and elaboration of these principles would make possible modern stratigraphy and geological mapping. Georgius Agricola, latinized form of Georg Bauer (1494-1555), a physician and geologist born in Glauchau, province of Saxony, made fundamental contributions to stratigraphic geology, mineralogy, structural geology, and paleontology. His greatest work, De Re Metallica ("On the Nature of Metals"), posthumously published in 1556, is a systematic study of ore deposits and of strata, and was to remain the standard text on mining geology for two centuries. In his profusely illustrated book Agricola noted that rocks were laid down in definite layers, or strata, and that these layers occurred in a consistent order and could be traced over a wide area. Agricola's observations would become important in understanding the arrangement and origins of the rocks of the Earth. Agricola is considered the founder of geology as a discipline. In the mid-16th Century the first engravings of fossils were published by the Swiss physician Conrad Gessner (1516-1565). Nicholaus Steno, latinized form of Niels Stensen (1638-1686), a Danish anatomist and geologist, who in Italy was converted to Roman Catholic faith and became a Roman Catholic prelate, pointed out the true origin of geological strata and of fossils. He wrote the first real geological treatise in 1667, while living in Tuscany, Italy. In 1669 he was the first recorded person to apply to the study of a sedimentary rock outcrop what is now referred to as Steno's law of superposition which states that layers of rock are arranged in a time sequence, with the oldest on the bottom and the youngest on the top, unless later processes disturb this arrangement, his most famous contribution to geology. In addition, Steno postulated other general principles of Stratigraphy: the principle of original horizontality, which states that rock layers form in the horizontal position, and any deviations from this position are due to the rocks being disturbed later; and the principles of strata continuity (material forming any stratum was continuous over the surface of the Earth unless some other solid bodies stood in the way) and cross-cutting relationships (if a body or discontinuity cuts across a stratum, it must have formed after that stratum). The data and conclusions of Steno's work on the formation of rock layers and fossils were crucial to the development of modern geology, and were enough to have earned him the title of 'Father of Stratigraphy'. Steno's contemporaries, the British natural scientists John Ray (1628-1705), Robert Hooke (1635-1703) and John Woodward (1668-1728),also argued that fossils were the remains of once-living animals and plants. However, the opinion was still universal that fossils represented life destroyed by the Universal Flood, a theory championed especially by the Swiss naturalist Johann Jakob Scheuchzer (1672-1733). Robert Hooke was perhaps the greatest experimental scientist of the seventeenth century. He was the first person to examine fossils with a microscope, to note close similarities between the structures of fossil and living wood and mollusc shells, and to observe, two and a half centuries before Darwin, that the fossil record documents the appearance and extinction of species in the history of life on Earth.
