200 



NATURE, OCCURRENCE, AND ORIGIN OF ALUNOGEN. 



roasting under certai?\ conditions is converted into a valuable 

 potash fertiliser the importance of finding a reasonably 

 high grade and extensive deposit is obvious. 



As the Vandyke alunogen deposit had not been geolog- 

 ically examined and the origin of the aluminium sulphate- 

 was not known, the opportunity afforded the writer in 

 August, 1917, of visiting and examining the deposit was 

 gladlj' availed of. The deposit is in portion 9, parish of 

 Osmondthorpe, at Vandyke holding, the property of 

 Kavanagh Bros. Mr. Michael Kavanagh guided me to 

 the deposit which is about 16 miles south-east of Spring 

 sure. 



Text-Fig. 30— View of the sandstone cliff, showing the incrustation 

 of alunogen. The top layer, from two to three feet thick, is formed of 

 conglomerate and is free from any alunogen incrustation. 



The alunogen is known to occur at three distinct 

 hillocks in the same locality and each one is about one half- 

 mile distant from the other two. The deposit visited was 

 the main one and the occurrence of all three deposits is 

 similar according to Mr. M. Kavanagh. The alunogeit 



