[1] The Catoctin Formation lies over a granitic basement rock and below the Chilhowee Group[1] making it only exposed on the outer parts of the Blue Ridge.

This formation contains iron oxide, dark, phyllite along thin beds of arkosic quartzite and layers of conglomerate rock.

[5] The Catoctin Formation found under the Chilhowee Group and above the basement rock(1.2-1.0 Ga) and is around 100–400 feet in thickness.

These dikes of greenstone are made up of pyroxene and plagioclase with chlorite and small amounts of calcite, quartz, and epidote.

Many of these dikes found in the formation have columnar jointing, faint cleavage, and are fine grained.

When placed under a microscope the rock shows original plagioclase that has been replaced with sericite and some darker opaque material.

The sedimentary dikes are found to be about 3 inches in width and have sediment that is the result of overlying the lava flow.

Other sedimentary dikes can be found at the base of flows that lead into the greenstone through a series of veins.

The greenstone that is darker and finer is where glass started forming due to the high temperatures from lava that came in contact with the sediments.

[4] Amygdules found in the greenstone of the Catoctin Formation are filled with quartz, epidote, albite, calcite, and chlorite.

They have an oval shape that has more round upper surfaces and longer bottoms parallel to jointing.

[4] The Catoctin Formation is mostly fine grained and has a massive structure in most places except where it is slaty or mylonitic.

[2] Catoctin hydrothermal alteration throughout the formation tends to be fine-grained but there are some places where clasts of feldspar have grown large and taken over most of the rock.

Amygdules in the formation are usually elliptical and contain quartz, feldspar, and epidote mainly but also can contain hematite, chlorite, chalcopyrite, malachite, and zeolite.

Altered pyroxene in rocks indicates granular crystals or basaltic glass texture found filling the spaces between plagioclase.

[6] The Catoctin Formation has porphyritic flows and sedimentary members that can be found north of Rose River and have a slight dip direction to the south-east.

Two primary faults can be found from Hawksbill Gap to Cedar Run and through Franklin Cliffs to Rose River.

Neoacadian Orogeny at 375 Ma occurred which caused deformation and metamorphism to the Catoctin Formation.

The last big deformation event came from Atlantic rifting that lead to fracturing within the Catoctin Formation around 200 million years ago.

Sediments found at the base of the formation are poorly sorted rocks that contain arkoses, conglomerates, and graywackes.

The bottom of the Catoctin Formation in other places shows a much larger accumulation of sediments such as the ones found near the head of Hawksbill Creek where the rocks are around 100 feet thick.