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