460 ME. H. II. BEAD OTf THE [vol. lxxix, 



veining of large hornfels-blocks by threads of contaminated rock ; 

 a second of a 1 it-par-lit complex, with perhaps equal amounts of 

 sediment and magmatic rock ; and a final stage of a somewhat 

 homogeneous rock, with only small ghosts of xenoliths left. A good 

 deal of quartz occurs as knots, nests, and stringers, as if it Avere 

 rejected in the contamination-process. 



(2) Wood, east of Waulkmill of Savoch. — Here, in 

 addition to the beerbachitic gabbro and the quartz-gabbro already 

 described from this locality, there are several varieties of quartz- 

 cordierite-biotite-felspar-rock, with many ghosts of xenoliths and 

 considerable quartz-nests. Farther south along the Ebrie Burn, 

 similar xenolithic garnetiferous contaminated rocks are seen. 



(3) Carding Hill, a third of a mile north-east of 

 Arnage Station. — This conspicuous hill provides very good 

 exposures of garnetiferous xenolithic contaminated rocks, rich in 

 biotite ; fluxional structures appear to run north-east and south- 

 west. 



(4) Arnage Station Quarry, 300 yards south-west of 

 Arnage Station. — Very beautiful and fresh specimens of 

 garnetiferous contaminated rocks are obtainable here ; they show 

 a well-marked fluxional structure running north-north-east and 

 south-south-west ; there seems to have been a very thorough 

 kneading of matrix and xenoliths, and thus the latter tend to occur 

 as Avisps, films, or pulled-out ' ghosts.' 



(5) GralloAV Hill, betAveen the railway and the Ebrie 

 Burn, two-thirds of a mile south-south-west of Arnage 

 Station. — Many A 7 arieties of contaminated rocks are exposed here, 

 some fine-grained, some extremely coarse, some Avith a multitude 

 of xenoliths, some practically homogeneous. There is often a 

 tendency to banding or fluxional structure, but no definite orienta- 

 tion was observed. 



(6) Kirk Hill and Hilton Croft Quarry, betAveen the 

 Arnage and Little Arnage kernels. — Good exposures of 

 coarse biotitic garnetiferous contaminated rocks, and many other 

 varieties, one of Avhich is porphyritic, are seen at these localities. 

 Fine blue hornfelses can be collected in Hilton Croft Quarry. 



(7) The Ardgrain-Elphin section, 2^ miles north of 

 Ellon. — On the rough ground along the road leading from Upper 

 and Nether Ardgrain to Elphin are abundant rock-exposures Avhich 

 show a perfect gradation from Ellon gneiss on the south-east into 

 contaminated rock on the north-Avest. Starting at the Ellon gneiss 

 and going north-north-Avestwards, we find first gneisses, delicately 

 lit- par -lit injected and A'eined by threads of igneous contaminated 

 rock, exposed south of Upper Ardgrain. These igneous injections 

 increase in abundance north-Avestwards, so that at the farm itself 

 there are good massive contaminated rocks Avith xenoliths of horn- 

 felsed gneiss. Similar rocks are seen on the Hill of Ardgrain 

 north-east of the farm. On a line north-north- west from the farm 

 to the top of Elphin Hill the rocks exposed are coarse garnetiferous 

 mixtures, Avith abundant hornfels xenoliths ; these xenoliths preserve 



