MINERALOGICAL QUERIES. II 3 



6. To what formation do the Castle-rock of 

 Edinburgh and the Calton-hill belong ? 



A part of the Calton-hill appears to belong to 

 the newest flcetz-trap formation. The principal 

 rocks are trap-turf, amygdaloid, and porphyry- 

 slate ; but we have still to ascertain, whether or 

 not the whole hill belongs to this formation, and 

 also the nature of its fundamental rock. It would 

 seem that the Castle-rock of Edinburgh is also 

 a portion of the same floetz formation as the Cal- 

 ton-hilL 



7. To what formation do Braid-hills, Black- 

 ford-hills, and Graig-Lockart, near Edin- 

 burgh, belong ? 



It is probable, from observations I have made 

 in these hills, that they belong to the newer flcetz 

 rocks. 



8. Does the greenstone of Corstorphin-hill be- 

 long to the independent coal-formation ? 



9. Does the Bass-rock at the mouth of the 

 Frith of Forth belong to the newest floetz- 

 trap formation ? 



From the observations of Dr Ogilby, it would 

 appear that clinkstone occurs at the Bass ; and 

 hence it is probable that a portion or the whole 

 of that isle, belongs to t the newest floetz-trap for 

 mation. 



