Cox. — On the Mineralogy of Neiv Zealand. 371 



At Mokau the coal seams vary from 2 feet to 6 feet in thickness, and a 

 trial of the coal against Waikato showed it to be one-fourth better, 1^ tons 

 of the Mokau coal doing as much as 2 tons of the best Waikato (Hector, 

 Geol. Eep. 1879-80, p. 21). The composition of these coals is — 



Fixed carbon . . . . . . . . 52-10 



Hydro-carbon . . . . . . 34-00 



Water 11-20 



Ash .. .. 2-70 



100-00 



At Whangarei two mines are at present at work — viz., Kamo mine, in 

 which there are two seams 4 feet to \.\ feet and 8 feet to 12 feet thick respec- 

 tively ; and the Whau Whan mine, in which the seam is from 5 feet to 9 feet 

 thick ; besides which outcrops of coal occur at Whareora 3 feet to 3 feet 6 

 inches thick ; and at Hikurangi, ten miles from Whangarei, there are 

 numerous outcrops of coal from 2 feet to 6 feet thick. 



The average composition of these coals from a number of analyses 

 is: — 



Fixed 

 carbori. 



Hydro- 

 carbon 



Water. 



Ash. 



Kamo .. .. 48-83 



38-60 



8-98 



3-59 



Whau Whau . . 47-50 



41-45 



7-59 



3-46 



Whareora . . 45-94 



38-79 



7.06 



8-21 



Hikurangi . . 43-41 



45-67 



6-16 



4-76 



making the average analysis of the 



coals from 



the Whangarei 



field— 



Fixed carbon . . 





. . 46-42 





Hydro-carbon . . 





. . 41-13 





Water 





7-45 





Ash 





5-00 





100-00 

 Anhydrous Coals. 

 Glance Coals. — These, which are brown coals, altered variously in the 

 vicinity of certain dykes and floes of dolerite, are only met with as workable 

 seams in the Malvern Hills coalfield, where they occur as seams from 2 feet 

 to 10 feet thick. They occur in all stages of change from brown coals to 

 anthracites, and some of them might, with propriety, be classed under the 

 subdivision of pitch coals, but since they all belong to a series, I have 

 thought it better to group all that have undergone any degree of change 

 under the present head, those in which the percentage of water is high 

 being left with the brown coals. Some of these with a high percentage of 

 water however, exhibit signs of change, the percentage of fixed carbon to 

 hydro-carbon being large, as in the case of the seams at the Eakaia Gorge, 

 already quoted. The following table of analyses shows how varied they are 



