ClipArt ETC
An ancient radiate from the Carboniferous Age, the Actinocrinus proboscidialis.

Actinocrinus Radiate

An ancient radiate from the Carboniferous Age, the Actinocrinus proboscidialis.

A radiate from the Paleozoic time, Caryocrinus ornatus.

Caryocrinus Radiate

A radiate from the Paleozoic time, Caryocrinus ornatus.

A radiate from the Paleozoic time, Chaetetes lycoperdon.

Chaetetes Radiate

A radiate from the Paleozoic time, Chaetetes lycoperdon.

A radiate from the Paleozoic time, Favosites Niagarensis of the Niagara group.

Favosites Radiate

A radiate from the Paleozoic time, Favosites Niagarensis of the Niagara group.

A radiate from the Paleozoic time, Halysites catenulata.

Halysites Radiate

A radiate from the Paleozoic time, Halysites catenulata.

A radiate from the Paleozoic time, Lecanocrinus elegans.

Lecanocrinus Radiate

A radiate from the Paleozoic time, Lecanocrinus elegans.

An ancient radiate from the Carboniferous Age, the Lithostrotion Canadense.

Lithostrotion Radiate

An ancient radiate from the Carboniferous Age, the Lithostrotion Canadense.

A mollusk radiate from the Paleozoic time, Stictopora acuta.

Mollusk Radiate

A mollusk radiate from the Paleozoic time, Stictopora acuta.

A mollusk radiate from the Paleozoic time, Orthoceras junceum.

Mollusk Radiate

A mollusk radiate from the Paleozoic time, Orthoceras junceum.

An ancient radiate from the Carboniferous Age, the Pentremites pyriformis.

Pentremites Radiate

An ancient radiate from the Carboniferous Age, the Pentremites pyriformis.

A radiate from the Paleozoic time, Petraia corniculum.

Petraia Radiate

A radiate from the Paleozoic time, Petraia corniculum.

A radiate from the Paleozoic time, Zaphrentis bilateralis of the Clinton group

Zaphrentis Radiate

A radiate from the Paleozoic time, Zaphrentis bilateralis of the Clinton group

An ancient radiate from the Carboniferous Age, the Zeacrinus elegans.

Zeacrinus Radiate

An ancient radiate from the Carboniferous Age, the Zeacrinus elegans.

"The impressions of the large rain-drops of a short shower made on a half-dry mud, have often been preserved in the rocks." -Dana, 1883

Rain Prints

"The impressions of the large rain-drops of a short shower made on a half-dry mud, have often been preserved…

A mollusk radiate from the Paleozoic time, Raphistoma lenticularis.

Raphistoma Mollusk

A mollusk radiate from the Paleozoic time, Raphistoma lenticularis.

Principal forms of the isometric system: rectangular prism.

Rectangular Prism

Principal forms of the isometric system: rectangular prism.

Rhodonite.

Rhodonite

Rhodonite.

"Triclinic. Crystals commonly tabular parallel to base." — Ford, 1912

Rhodonite

"Triclinic. Crystals commonly tabular parallel to base." — Ford, 1912

"The vertical crystallographic axis is one of trigonal symmetry, and the three horizontal crystallographic axes of binary symmetry." — Ford, 1912

Symmetry of Rhombohedral Class

"The vertical crystallographic axis is one of trigonal symmetry, and the three horizontal crystallographic…

Principal forms of the hexagonal system: rhomohedron.

Rhombohedron

Principal forms of the hexagonal system: rhomohedron.

"The rhombohedron is a form consists of six rhombic-shaped faces, which correspond in their position to the alternate faces of a hexagonal pyramid of the first order. There may be two different orientations of rhombohedron. A negative rhombohedron is shown." — Ford, 1912

Negative rhombohedron

"The rhombohedron is a form consists of six rhombic-shaped faces, which correspond in their position…

"The rhombohedron is a form consists of six rhombic-shaped faces, which correspond in their position to the alternate faces of a hexagonal pyramid of the first order. There may be two different orientations of rhombohedron. A positive rhombohedron is shown." — Ford, 1912

Positive rhombohedron

"The rhombohedron is a form consists of six rhombic-shaped faces, which correspond in their position…

A mollusk radiate from the Paleozoic time, Rhynchotreta cuneata from the United States and Great Britain.

Rhynchotreta Mollusk

A mollusk radiate from the Paleozoic time, Rhynchotreta cuneata from the United States and Great Britain.

Marks made by water spreading over shells of stones that are lodged in the sand, in this image in Silurian sandstone.

Rill Marks

Marks made by water spreading over shells of stones that are lodged in the sand, in this image in Silurian…

The marks created in mud or sand by flowing water, often found in sandstone.

Ripple Marks

The marks created in mud or sand by flowing water, often found in sandstone.

"View on Roche-Mouttonnee Creek, Colorado." -Dana, 1883

Roche-Moutonnee Creek

"View on Roche-Mouttonnee Creek, Colorado." -Dana, 1883

"Diagrammatic structure section of the Wasatch Range in Ogden Canyon." -Lee, 1915

Rock Layers Showing Geological Periods

"Diagrammatic structure section of the Wasatch Range in Ogden Canyon." -Lee, 1915

"Cross section of Marsh Creek valley at McCammon, Idaho." -Lee, 1915

Rock Layers Showing Types of Rock

"Cross section of Marsh Creek valley at McCammon, Idaho." -Lee, 1915

Basaltic rock is a common extrusive volcanic rock. Fingal's Cave is a sea cave composed of basaltic rocks on the uninhabited island of Staffa, in the Inner Hebrides of Scotland. It has a naturally arched roof, and with the eerie sounds produced by the echoes of waves, it has the atmosphere of a natural cathedral.

Basaltic Rock

Basaltic rock is a common extrusive volcanic rock. Fingal's Cave is a sea cave composed of basaltic…

Diagram showing the interrelations of the Endogenetic rocks.

Endogenetic Rocks

Diagram showing the interrelations of the Endogenetic rocks.

An illustration of a group of three rocks.

Group of Rocks

An illustration of a group of three rocks.

Rutile.

Rutile

Rutile.

"Tetragonal. Usually prismatic with pyramid terminations." — Ford, 1912

Rutile

"Tetragonal. Usually prismatic with pyramid terminations." — Ford, 1912

"This form consists of twelve scalene triangular faces. These faces correspond in their position to the alternate pairs of faces of a dihexagonal pyramid." — Ford, 1912

Scalenohedron

"This form consists of twelve scalene triangular faces. These faces correspond in their position to…

Principal forms of the hexagonal system: scalenohedron

Scalenohedron

Principal forms of the hexagonal system: scalenohedron

"A crystal of scapolite, upon which the faces of the third-order pyramid are shown." — Ford, 1912

Scapolite

"A crystal of scapolite, upon which the faces of the third-order pyramid are shown." — Ford, 1912

"Tetragonal; tri-pyramidal. Crystals usually simple pyramids of first order. Closely resemble isometric octahedrons in angles. Faces of the pyramid of third order are small and rare." — Ford, 1912

Scheelite

"Tetragonal; tri-pyramidal. Crystals usually simple pyramids of first order. Closely resemble isometric…

"This is a form consisting of six rectangular vertical faces, each of which intersects two of the horizontal axes equally and the immediate horizontal axis at one half this distance." — Ford, 1912

Prism of the second order

"This is a form consisting of six rectangular vertical faces, each of which intersects two of the horizontal…

"This is a form composed of twelve isoceles triangular faces, each of which intersects two of the horizontal axes equally, the third and immediate horizontal axis at one-half this distance, and also intersects the vertical axis." — Ford, 1912

Pyramid of the second order

"This is a form composed of twelve isoceles triangular faces, each of which intersects two of the horizontal…

One of the founders of modern geology.

Adam Sedgwick

One of the founders of modern geology.

The floor of the sea was first formed or rocks that had cooled from a state of fusion. The few islands that existed were but exposed portions on the floor. The debris scattered over this foundation would be arranged in layers, as water always arranges its sediments. The coarser materials would be transported by the more powerful action and deposited in one place. The finer materials would be carried beyond and deposited in a remoter region. Here we see (a) the primordial igneous crust, (b) a sea-side cliff gnawed by the waves, (c) the ordinary sea-level, (d) the ruins of the cliff with the coarser deposited near the shore, and the finer floated to greater depths.

Shore Erosion and Distribution of Sediments

The floor of the sea was first formed or rocks that had cooled from a state of fusion. The few islands…

"inverted Vertical Pendulum Seismograph. Marvin System. A stiff vertical tube, pivoted at its bottom end, carries a very heavy mass near its upper end, and is rendered stable or astatic by the elastic reaction of a central steel rod which has its bottom end firmly fixed inside the heavy mass and its top end attached to the framework on the pier. The horizontal motion of the ground and pier relative to the steady mass is magnified 120 times and inscribed on smoked-paper record-sheets by two sets of multiplying levers. One records the north-south, the other the east-west component of motion." -Whitney, 1911

Pendulum Seismograph

"inverted Vertical Pendulum Seismograph. Marvin System. A stiff vertical tube, pivoted at its bottom…

"Shear is a particular form of strain produced by causing plane layers of a material to slide parallel to one another through spaces proportional to their distances from a fixed parallel plane"—Finley, 1917

Shear

"Shear is a particular form of strain produced by causing plane layers of a material to slide parallel…

"A crumb of soil (magnified). The white spaces represent air."—Finley, 1917

Crumb of soil

"A crumb of soil (magnified). The white spaces represent air."—Finley, 1917

"Isometric; tetrahedral. Tetrahedron form." — Ford, 1912

Sphalerite

"Isometric; tetrahedral. Tetrahedron form." — Ford, 1912

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes, the intercepts on the two horizontal axes being equal. The faces correspond in their position to the alternating faces of the tetragonal pyramid of the first order." — Ford, 1912

Sphenoid

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes,…

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes, the intercepts on the two horizontal axes being equal. The faces correspond in their position to the alternating faces of the tetragonal pyramid of the first order." — Ford, 1912

Sphenoid

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes,…

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes, the intercepts on the two horizontal axes being equal. The faces correspond in their position to the alternating faces of the tetragonal pyramid of the first order. There maybe different sphenoids, depending upon their varying intersections with the vertical axes. There may also be a positive and a negative sphenoid, the combination of the two being represented." — Ford, 1912

Sphenoid, positive and negative

"It consists of four isoceles triangular faces which intersect all three of the crystallographic axes,…

"The Sphenoidal Class corresponds in the Tetragonal system to the Tetrahedral class in the Isometric System. It is characterized by the following symmetry: The three crystallographic axes are axes of binary symmetry, and there are two vertical diagonal planes of symmetry." — Ford, 1912

Symmetry of Sphenoidal class

"The Sphenoidal Class corresponds in the Tetragonal system to the Tetrahedral class in the Isometric…

An ancient mollusk from the Paleozoic time, Spirifer mucronatus.

Sprifer Mollusk

An ancient mollusk from the Paleozoic time, Spirifer mucronatus.

Two cases of springs: "In one, the water descends through the porous bed e to the layer d, which is relatively impervious. The water flows along this layer until it comes to the surface, and there the water flows out as a spring, s'. In the other, the water moves underground through the porous layer b, under pressure, until it reaches a crack which leads up to the surface...s." -Salisbury, 1919

Springs

Two cases of springs: "In one, the water descends through the porous bed e to the layer d, which is…

A Radiate Echinoderm, the starfish, Paleaster Niagarensis.

Starfish

A Radiate Echinoderm, the starfish, Paleaster Niagarensis.

Staurolite.

Staurolite

Staurolite.

"Orthohombic. Habit prismatic, showing usually a combination of prism with large angle, brachypinacoid, base and macrodome." — Ford, 1912

Staurolite

"Orthohombic. Habit prismatic, showing usually a combination of prism with large angle, brachypinacoid,…

"Monoclinic. Uniform in cruciform twins. Commonly tabular parallel to clinopinacoid. Crystals usually in sheaflike aggregates." — Ford, 1912

Stilbite

"Monoclinic. Uniform in cruciform twins. Commonly tabular parallel to clinopinacoid. Crystals usually…

This image shows the foldings in strata.

Strata Folding

This image shows the foldings in strata.

Anticlinal strata is a geological fold upwards with the oldest layer at the core.

Anticlinal Strata

Anticlinal strata is a geological fold upwards with the oldest layer at the core.

Synclinal strata is a geological fold downwards.

Synclinal Strata

Synclinal strata is a geological fold downwards.

"In some places a series of strata A, having a certain dip, rest directly upon the eroded surface of another series, having the same dip." — Hinman, 1888

Uncomformable strata

"In some places a series of strata A, having a certain dip, rest directly upon the eroded surface of…

"Unconformability between horizontal and inclined strata. Inferior Oolite (a b) resting on Carboniferous Limestone (c); Frome, Somerset." -Geikie, 1893

Unconformable Strata

"Unconformability between horizontal and inclined strata. Inferior Oolite (a b) resting on Carboniferous…