446 Extracts from the Minute Book of the Geological Society. 



Renfrewshire. The strata of the four places vary indeed in thick- 

 ness, but their position and alternation may be considered the same. 

 A sketch of the Campsie strata is subjoined, as descriptive of the 

 whole. 



After passing through the soil and one foot of limestone, alternating strata 

 of Bituminous Schistus and ironstone occur, till we arrive at the immediate 

 vicinity of the aluminous materials ; which are, 



Limestone 4 feet 



Aluminous schistus, which consists of (what the miners call) 



the gentle slate, and the diamond slate ... 2 



Coal, of the caking quality of the Newcastle, which contains 



the slaty and the nodular pyrites .... 4 



Fire Clay of excellent quality ..... 1 



The coal has been extensively excavated for a long series of 

 years, from mines of which the temperature is seldom under 60° 

 Fahr. frequently as high as 80°, in places excluded from any direct 

 current of air. The circulation of this warm air has ripened the 

 hard slate into various qualities, and these contain proportions of 

 alum and copperas, which vary according to the time of their expo- 

 sure, the recent slates abounding in copperas, those longer exposed, 

 in aluminous matter. 



1815, April 7. 



A notice was communicated by Leonard Horner, Esq. respecting 

 the rocks of the Isle of Tino, in the Archipelago. 



The highest part of Tino is one long ridge of limestone, which 

 affords excellent marble, that is sent for grave-stones to Smyrna 

 and Constantinople. In the garden of an Italian convent there is a 

 beautiful vein of asbestos running through serpentine, which passes 

 into a kind of verde antique. It is stratified and dips westward 



