I EXPLANATION OF THE GEOLOGICAL MAP. Mil 



Map shall be prepared, showing the courses and limits of the quartxitfl 



and slate bands, of the gneiss and mica-slate, and of the many irre- 

 gular dikes and masses of granite and other eruptive rocks, it will 

 present an appearance marvellously intricate and complex, in com- 

 parison with the broad colouring of the present Map. In the 

 meantime, 1 have been enabled to improve the limit lines formerly 

 given, by reference to the papers of J3r Honeyman, and the Reports 

 presented to the Government of Nova Scotia by Mr Poole and Mr 

 Campbell, to which I may also refer for a great number of minor 

 details of distribution which I could not introduce in the Map. 



The only area in Nova Scotia coloured as Devonian is that of 

 Nictaux and its vicinity in the west. There are, however, at and near 

 the limits of the Silurian and Carboniferous, in the eastern part of the 

 province, many spaces which may be of this age, but which 1 am not 

 able to separate from the Upper Silurian and Carboniferous, and have 

 therefore left as in the former Map. Areas of this kind occur in 

 Colchester, in Pictou, and, according to Dr Honeyman, in Antigonisli, 

 and have been mentioned in the text, though I must leave their 

 delineation on the Map to future and more detailed researches. In 

 the Carboniferous areas I have thought it best not to adopt, as in 

 many recent Maps, a distinct colour for the Lower and Upper Car- 

 boniferous ; but have included the whole under one tint, as constituting 

 one great geological system. The propriety of this will, I think, be 

 obvious, when it is considered that the lines of separation between the 

 subdivisions of the Carboniferous are not sharp and definite, that 

 marine beds coeval with the Coal formation may readily be confounded 

 with the true Lower Carboniferous, and that new discoveries are 

 constantly being made, which show that more local intermixture of 

 the several members of the Carboniferous exists than had been sus- 

 pected. The boundary of the Lower Carboniferous has, however, 

 been indicated by a dotted line, and special marks show the position 

 of the principal beds of marine limestone, and of the more important 

 beds of coal. 



Considerable beds of interstratified trap occur in the Lower 

 Carboniferous of Nova Scotia and New Brunswick. They are in- 

 cluded under the general colouring, in consequence of their small 

 superficial extent, and the uncertainty of their limits. The only 



