| Computer Code: |
BLSL |
Preferred Map Code: |
BLSF |
| Status Code: |
Full |
| Age range: |
Ordovician Period (O)
— Ordovician Period (O) |
| Lithological Description: |
Slate, black, graphitic, with pyrite and locally abundant chert laminae, and subordinate grey and pale green arenite near top. Lenses of spilite and amphibolite occur locally. Locally fossiliferous with a brachiopod faunal assemblage. |
| Definition of Lower Boundary: |
Incoming of dominant black slate and chert and the outgoing of pale arenites at top of Loch Ard Grit Formation. Probable faulted contact with Dalradian. |
| Definition of Upper Boundary: |
Appearance of carbonated serpentinite and jasper-rich rock of the Lime Hill Serpentinite; contact probably faulted. |
| Thickness: |
600m maximum |
| Geographical Limits: |
Southwest of Aberfoyle and northwest of the Highland Boundary Fault; not known beyond western margin of Sheet 35E. |
| Parent Unit: |
Highland Border Complex (HBX)
|
| Previous Name(s): |
Black Slate and Chert [Obsolete Name and Code: Use BLSL]
(-4473)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Partial Type Section |
Stream section of Bofrishlie Burn, Loch Ard Forest, Aberfoyle. |
| Reference(s): |
| Jehu, T J and Campbell, R, 1917. The Highland Border rocks of the Aberfoyle District. Transactions of the Royal Society of Edinburgh, Vol.52, 175-212. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
S038
|
