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Schematic diagram of the human eye. It shows a horizontal section through the right eye. The eye is made up of three coats, or layers, enclosing various anatomical structures. The outermost layer, known as the fibrous tunic, is composed of the cornea and sclera, which provide shape to the eye and support the deeper structures.
Stratigraphic sections can also be used to locate areas for water, coal, and hydrocarbon extraction, particularly petroleum and natural gas. A Global Boundary Stratotype Section and Point (GSSP) is an internationally agreed upon reference point on a stratigraphic section which defines the lower boundaries of stages on the geologic time scale. [5]
The posterior segment or posterior cavity [1] is the back two-thirds of the eye that includes the anterior hyaloid membrane and all of the optical structures behind it: the vitreous humor, retina, choroid, and optic nerve. [2]
The anterior segment or anterior cavity [1] is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens. [2] [3] Within the anterior segment are two fluid-filled spaces: the anterior chamber between the posterior surface of the cornea (i.e. the corneal endothelium) and the ...
A cross section or cross-section, in geology, is a diagram representing the geologic features intersecting a vertical plane, and is used to illustrate an area's structure and stratigraphy that would otherwise be hidden underground. The features described in a cross section can include rock units, faults, topography, and more.
During the 17th century, Nicolas Steno was the first to observe and propose a number of basic principles of historical geology, including three key stratigraphic principles: the law of superposition, the principle of original horizontality, and the principle of lateral continuity.
Stratigraphy is a branch of geology concerned with the study of rock layers and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks . Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy ...
section A section is a view of the archaeological sequence showing it in the vertical plane, as a cross section, showing the stratigraphy. sherd See potsherd shovel test pit test holes, usually dug out by a shovel, in order to determine whether the soil contains any cultural remains that are not visible on the surface. shovelbum