skip all navigation
skip banner links
skip primary navigation

rockin logoVirtual Field Trip—Group 5
Geologic Features of the Holder Formation

 

Fusulinids

Ken Stanley

GPS Location: 13S, 0414457, UTM 3649818

Small “spindle shaped” calcareous marine fossils that resemble grains of rice or wheat. Fusulinids are single cell organisms.

Crinoid

Crystal Cobble

GPS Location: 13 S, 0414417, UTM 3649825

Pennsylvanian crinoids are related to modern day sea lilies. They are members of the echinoderm family. All crinoids are constructed of a single crystal of calcite. In this photo, you can see a single column with a central canal.

Brachiopods

Azza Ezzat and Ronda Gillespie

GPS Location: 13 S, 0414417, UTM 3649825

Visible in these photographs, typical brachiopod have a concave fan-like shape. Each valve of the brachiopod has bilateral symmetry.

Limestone Cycle

Nicole Erdelyi

GPS Location: 13 S, 0414457, UTM 3649818

In this picture, you can see limestone with thin layers of sandstone and shale in a cycle due to a change in sea level. Phylloid algae are very apparent in each of the limestone layers.

Phylloid Algae

Dusti Griffin

GPS Location: 13 S, 0414417, UTM 3649825

This is an example of remains of the phylloid algae that once lived in this area. They appear to have a “potato chip” shape when viewed from the edge.

Conglomerate

Robert Tcherneshoff

GPS Location: 13 S, 0414457, UTM 3649818

The conglomerate found on the northern side of the outcrop was formed in an ancient streambed or at a low sea level when the shelf was exposed. There are small “holes” that were formed from more soluble cobbles that dissolved.

Shelf “Sandwich”

Ronda Gillespie

GPS Location: 13 S, 0414457, UTM 3649818

This shelf “sandwich” is created using rocks from each type of layer represented in this outcrop.

Back to Group 5 Overview
Back to VFT Home