Vol. 50.] PICEIXE AND ASSOCIATED ROCKS AT BABNTON. 



39 



4. On a Piceite and othee associated Rocks at Barnton, near 

 Edinburgh. By Hoeace W. Monckton, Esq., F.L.S., E.G.S. 

 (Read December 6th, 1893.) 



Tdje Barnton Branch of the CaledoDian Railway leaves that Com- 

 pany's Edinburgh and Leith line immediately north of Craigleith 

 Station, opposite to Sir James Maitland's great Craigleith Quarry. 

 The Barnton line lies almost entirely on Sir James's property, and 

 I have to thank him for assistance in collecting the facts I now 

 record. On our last visit to the locality we first inspected a trial pit, 

 east of the old railway and close to it, a little north of Craigleith 

 Quarry. The section was as follows : — 



1. Sui'face-bed, with a few large boulders. 



2. Thinly-bedded sandstone, about 12 feet. 



3. Skaly beds, with an easterly dip of 1 in 4. 



The first cutting on the new line is about | mile from the 

 junction at Craigleith. It is 19 feet deep and entirely in Boulder 

 Clay. At from 3 to 4 feet below the top of the cutting there is a 

 remarkably even line of very large boulders, and in one place I noted 

 below them a patch of yellow sand 2 feet thick. The rest of the 

 sides of the cutting is formed of black clay, full of small stones. 



More Boulder Clay is shown between House 0' Hill and Drylaw, 

 but it is not till we reach Barnton Park that we find a section 

 showing the solid geology. In the first cutting in the park the 

 beds of the Calciferous Sandstone Series are seen dipping westward 

 at an angle of about 30°, and as I began my examination at the 

 eastern end they are here described in ascending order. 



Diagram-Section on the Barnton Railway in Barnton Parfci 



V v. A, -i y v x 





^Wgi^S®^^ 



11. Dolerite. 



10. Picrite, through which 



run veins of basalt. 

 9. Indurated shale. 

 8. Igneous rock. 

 7. Indurated shale or 

 ' calm.' 



6. Igneous rock, 1 foot 

 (inica-porphyrite). 



5. Indurated shale. 



4. Igneous rock, 12 feet 

 (lnica-poi-phyrite). 



3. Indurated shale. 



2. Black shale, with 

 veins of calcire, 



1. Thinly-bedded sand- 

 stone. 



Much of the shale of beds 3, 5, and 7 is of a whitish colour and 

 very hard, of the kind locally termed ; camstonc ' or ' calm.' A 

 similar rock is, I believe, quarried in Corstorphine Hill. 



Associated with this shale are some beds of igneous rock. Micro- 

 sections have been made from bed No. 4 and from bed No. (3. 



