L311 Conglomerate

Poorly sorted. Rounded clasts up to ~15 mm long. 
Pale yellow matrix of quartz grains. 
Cement fizzes with acid, indicating that it contains carbonate. 
This conglomerate is just clast-supported.

Rounded clasts of very dark red brown amorphous silica (chert) and polycrystalline quartz.

Matrix of quartz grains (typically 0.25 mm) and fine-grained carbonate cement (sparite). Dark red-brown iron staining.

Deposited in a high energy environment.

Iron staining 
Hematite (Fe₂O₃) → red (blood-red, cherry-red, brown-red) iron-staining 
Limonite (FeO(OH)•nH₂O) → yellow or brown iron-staining

The red-brown colour of this rock is probably produced by hematite.

conglomerate