CATALOGUE OF PHILOSOPHICAL APPARATUS, &c. 17 



Drawer 10. Chiastolite Slate, destitute of organic remains, belonging to the 

 Cambrian series, Skiddaw, Cumberland. 



Drawer i i . Slate containing Graphite, Borrowdale ; and Limestone of 

 Coniston. 



Drawer 1 2. Silurian rocks with tubiporites, madreporites, &o. Lilleshall, 

 Shropshire. 



Drawer 13. Slates, Serpentines, &c. Cornwall. 



Drawer 14. Slates and Sandstones, underlying the Devonian system; from 

 the Gap of Dunloe, Killarney. 



Drawer 15. Silurian limestones from Connemara. 



Containing traces of Phosphoric Acid, mostly crystalline, and asso- 

 ciated with noble Serpentine (verd antique). The following is 

 the composition of a few of these specimens. 



The presence in these rocks of Phosphoric Acid is interesting, as showing, that the high 

 degree of metamorphic action which they must have undergone in order to convert them into 

 the crystalline condition in which they appear, has not disengaged their Phosphoric Acid ; 

 tending therefore to prove, that this substance, if once introduced into a rock from any source, 

 will remain undissipated, whatever heat the material may afterwards undergo. 



Drawer i 6. Silurian Slates from the border country of Scotland, Fassney 

 Burn, East Lothian; with Granite, or Sienitic Greenstone, 

 intruding into it in Dykes. 



Described in the Wernerian Transactions, vol. I. by Dr. Ogilvie, 

 under the name of Greywacke Slate. 



D 



