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VII. On the Transition Greenstone of 

 Fassney. 



By James Ogilby, M. D. 



(Read, loth December 1808.J 



In consequence of a query proposed by Profes- 

 sor Jameson, I was led to a minute examination of 

 a very interesting rock which occurs at Fassney- 

 burn, in that part of the Lammermuir range of 

 mountains forming the southern boundary of East 

 Lothian. For the purpose of exactly ascertaining 

 its geognostic situation, I began my examination 

 immediately below Herd's Hill, near the source 

 of the rivulet called Fassney which, at about three 

 miles north-east of this spot, has uncovered the 

 rock in question. This precaution was the more 

 necessary, as the same obstacle to the researches 

 of the mineralogist presents itself in this moun- 

 tainous district, as in other parts of the county of 

 East Lothian. The highest of the hills does not 

 much exceed 1500 feet. The rocks are decom- 



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