BGS mineralogy and petrology collection record

Sample number	E24531; COLLNOBN50;
Sample Donor	Bisson,G.
Rock name	'Original entry: Contact Altered Crystal Lithic Tuff Of Keratophyric Affinity'
Stratigraphy	Not entered
Comments	Tuff. Between 345 and 524 Ft. inside the W. portal.
Locality details	From dump at West end of Prewley Tunnel.
50k map sheet	Okehampton (324) View images in GeoScenic related to 'Okehampton' View the geology near 'Okehampton'
Map reference	SX 549 909
Year collected	Not entered
Bore name	Not applicable
Confidentiality	No restrictions

Petrological thin sections

Field of view: c. 31 mm.