Trill (Troll) Quarry SSSI

Trill (Troll) Quarry SSSI, Thornford.
Fuller’s Earth Rock.
ST 593 126

This is a key locality in studies of Bathonian (Middle Jurassic) stratigraphy. It shows sections through the Thornford Beds of the Fullers Earth Rock.

This has been defined as the type locality for the base of the standard Tulites subcontractus zone. The zonal index ammonite T . subcontractus is very common at the site.

Pholadomya lirata

Zone Subzone Group Formation Member
Callovian Macrocephalites herveyi

Macrocephalites kamptus Kellaways
Macrocephalites terebratus

Great Oolite Cornbrash Upper Cornbrash
Keppleritis keppleri
Upper Bathonian Clydoniceras discus

Clydoniceras discus Lower Cornbrash
Clydoniceras hollandi Forest Marble
Oxycerites orbis



Boueti Bed
Frome Clay
Procerites hodsoni
Wattonensis Beds
Fuller’s Earth Upper Fuller’s Earth
Fuller’s Earth Rock Ornithella Beds
Middle Bathonian Morrisiceras morrisi Linguifera Bed
Tulites subcontractus Thornford Beds
Procerites progracilis Lower Fuller’s Earth Acuminata Beds
Lower Bathonian Asphinctites tenuiplicatus 
Zigzagiceras zigzag


Oppelia (Oxycerites) yeovilensis Lenthay Beds
Inferior Oolite Crackment Limestones
Parkinsonia convergens

Great Oolite Group stratigraphy in the Sherborne area

The quarry face is now located within a Wessex Water operated sewage treatment works.

G C Rowland June 2021

Preserving our geological heritage