STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 129 



The analyses of Xew Zealand coals are proximate. Hector has 

 published those of samples taken from different parts of two im- 

 portant seams : 



The difference in volatile of I. and II., from the same bed, is un- 

 usually great. Cox has given the results of numerous analyses of 

 coals from the Buller field ; the coal is bituminous and that from 

 some mines is caking. The water content is very low, seldom ex- 

 ceeding 7 per cent. The ash is amazingly small, there being less 

 than one per cent, in 9 of the 14 samples and only 4 exceed two per 

 cent. Analyses of coals from Otago, as reported by Hutton, have in 

 most cases very little ash. One cannot resist the suggestion that the 

 samples may have been selected " average " lumps.^^^ 



Many thousands of analyses of coals have been made by the 

 United States Bureau of Mines and a great number have been made 

 for the Geological Survey of Canada. The samples consist of cuts 

 across the whole bed, omitting such partings or benches as should be 

 removed before shipment of fuel from the mine. For the most 

 part, the samples have been taken from mines in successful opera- 

 tion or, if the region be undeveloped, from such seams as gave 

 promise. The purpose of the sampling is to determine the com- 

 mercial value of the property and the method is beyond doubt the 

 best yet devised. But the student of geological relations should read 

 the descriptive portion of Bulletin 22 in order to learn how far the 

 analyses concern matters occupying his attention. 



The Laramie coals. The Laramie formation, as defined in pre- 

 ceding pages, contains at most localities only thin seams of coal ; 

 but in the northern part of the San Juan Basin of New Mexico 

 and Colorado as well as in the Edmonton region of Alberta, the 



136 J. Hector, New Zealand Reps, for 1871-2, pp. 132, 134; J. H. Cox, the 

 same, for 1874-6, p. 25 ; F. W. Hutton, " Geology of Otago," 1875, PP. ioi» 

 105, no. 



