BRITISH AVONIAN CONODONT FAUNAS 29 
(v) Scotland 
Rocks of Carboniferous age outcrop over much of the Midland Valley of Scotland. 
Strata of ‘“ Lower’ Carboniferous age lie below the Passage Group and Productive 
Coal Measures of the typical coalfield areas, but in places both the Passage Group and 
the Oil Shale Groups are replaced by contemporaneous lavas, chiefly of olivine 
basaltic composition. 
These strata were traditionally subdivided into two broad lithological series, 
the Calciferous Sandstone Series and an overlying Carboniferous Limestone 
Series. The lower of these divisions is now termed the Calciferous Sandstone 
Measures, and the upper division is no longer used on maps of the Geological Survey 
(MacGregor 1960). The lowest division of the Calciferous Sandstone Measures, the 
Cementstone Group, consists of alternating fine-grained dolomite and shales, whilst 
the overlying Lower and Upper Shale Groups consist of alternating series of sand- 
stones, shales, coals, fireclays and limestones. Both marine and fresh-water lime- 
stones occur and oil shales are widespread. The greatest thickness of the Groups is 
in the East Fife Coalfield where some 4,000 ft. of strata occur. 
The overlying strata (the “‘ Carboniferous Limestone Series ”’ of earlier authors) 
are subdivided into three lithological groups, the Lower Limestone Group, the Lime- 
stone Coal Group, and the Upper Limestone Group. The two higher groups each 
have a maximum thickness of some 1,500 ft. in the West Fife Coalfield, while the 
maximum thickness of the Lower Limestone Group is only some 700 ft. Like the 
Calciferous Sandstone Measures, the whole Carboniferous Limestone “ Series ’’’ thins 
rapidly southwestwards into the North Ayrshire Coalfield, where it is reduced in 
places to less than 100 ft. The Lower Limestone Group consists of thin marine 
, 
Rake Gey eae 
o> Anstruther 
Pittenween 
Glengarnock 
Dairy 
Machrihanish 
ROXBURGH 
3 2 miles oHarden 
Burn | 
Fic. 9. Outline map of Southern Scotland, showing localities mentioned in the text. 
