IN THE SOUTH OF SCOTLAND. 



441 



SUB-DIVISION OF THE UPPER SILURIAN KOCKS. 



Hi 

 g 



o ft 





Volcanic 



Series. 



3. Andesites and tuffs (volcanic zone). 



2. Chocolate-coloured sandstones with Cephalaspis 

 Lyelli. 



1. Conglomerate with greywacke pebbles. 



Unconformability in the Pentland Hills and in Ayrshire ; 

 apparent conformability in Lanarkshire. 



55 



^ 



w 

 P 



P4 



OH 



Downtonian. 



Ludlow. 



Weniock. 



/ll. Chocolate-coloured sandstones 1200 feet in Lesnia- 

 hagow iulier. 



10. Conglomerate with large pebbles of quartzite 100 

 feet in Lesmahagow inlier. 



9. Green and red mudstones, with bands of grey shale 

 and greywacke, containing seams with fishes and 

 crustaceans 100 feet in Lesmahagow inlier. 



8. Red and yellow false-bedded sandstones and red mud- 

 stones 1300 feet in Lesmahagow inlier. 



7. Conglomerate of local occurrence, with small pebbles 

 of Arenig volcanic rocks, radiolarian cherts, etc., 

 resting conformably on Ludlow shales 88 to 150 

 feet in the Hagshaw Hills anticline. 



I 6. Green flaggy and sandy greywackes, with partings of 

 grey and red mudst-one about 130 feet. 



5. Blue, grey, and green shales with sandy mudstones 

 and greywackes, occasionally weathering with a 

 rusty colour 200 feet (Trochus beds). 



4. Hard blue and grey flaggy shales and mudstones with 

 occasional bands of calcareous nodules 350 feet 

 (Pterygotus beds). 



3. Hard grey flagstones and bands of hard greywacke, 

 with bands and zones of dark fissile calcareous 

 flaggy shales, weathering rusty brown 500 feet 

 (Ctratiocaris beds and Ludlow fish-band). 



2. Grey, blue, and olive shales, with occasional greywacke 

 bands 300 feet. 



f 1. Hard bands of greywacke in the shale partings 1300 

 \ feet. 



Two lists of fossils are appended, one from the Weniock and Ludlow rocks 

 and the second from the Downtonian strata. 



