636 REPORT— 1891. 



Queensland. 

 Mr. E. L. Jack writes as follows : — 



" I object strongly to the proposed unification, for the fol- 

 lowing reasons : — 



" In the first place, it is impossible. Human ingenuity 

 could not foresee and provide for all the future requirements of 

 geological mapping. No hard-and-fast scale of colours could 

 be contrived by which all possible subdivisions of geological 

 formations could be denoted. 



"The colours and symbols used in any particular case will 

 always depend on the object of the map. In a general map of 

 Europe, for example, perhaps forty different colours might be 

 employed ; and the ingenuity of the geologist and colourist 

 would have to be exercised in contriving colours which would 

 (1) contrast sufficiently, and (2) at the same time group the 

 members of each formation or system under modifications of 

 one colour. But if, on the other hand, a geologist undertook 

 to map out in detail the various recognisable horizons of any 

 one system or formation — say, for example, the Carboniferous 

 system — he would require to make so many modifications of 

 the same colour that they would cease to present a sufficient 

 contrast. In such a case he would probably do best to 

 avail himself of colours which would contrast strongly and 

 at the same time present a pleasing and harmonious general 

 effect. 



"It is easy to imagine a case where a map of a limited area 

 — say, a twem'y-acre lease — showing the outcrops of all the 

 visible strata, might be valuable for mining purposes." Such a 

 map might be useful to a geologist, although it might be pre- 

 pared by a surveyor or miner possessing no particular know- 

 ledge of geology ; and its object would be best served by using 

 a series of colours plainly distinguishable from one another 

 without reference to the colour on the scale set apart for the 

 subdivision of the formation to which the strata belong- — a 

 matter which might not be within the knowledge of the con- 

 structor of the map, nor even ascertainable by a geologist. 



" A general unification of colours and signs implies an agree- 

 ment between the different formations and subdivisions all over 

 the world — in fact, the old ' coats of an onion ' idea, which, as 

 every geologist knows, is not tenable, and the attempt at uni- 

 fication W'Ould be a formidable difficulty in the way of depicting 

 homotaxial relations, or varying physical conditions, such as 

 contemporaneous elevation in one region and depression in 

 another. 



" In the second place, the proposed unification is undesirable 

 and unnecessary. It implies an absolute consensus of opinion 

 as to the position on the geological scale of every formation 



