Mineralogy and Geology of Nova Scotia. 591 



lowing that direction as far as necessary, continued to the 

 other side of Lawrence town River, about a mile farther south 

 than the present track, it would have been an easy road. 



Where slate rises in lofty hills, it frequently appears of a 

 pale colour near their summits, and, containing but a very 

 small proportion of pyrites, seldom acquires a rusty coat by 

 exposure. Most of the best hills in Preston rest upon a rock 

 of this kind; but, upon the lower part of the same hills, the 

 rock contains a full proportion of pyrites, and the soil is, of 

 course, of inferior quality. The basis of some hardwood hills 

 is a slate rock, containing a mixture of limestone, and no 

 vitriolic mineral. As the soil on these hills is fertile, it is use- 

 ful to be able to distinguish this variety of slate: it is always 

 of a light bluish colour, without rust. The limestone, which is 

 fine-grained, and nearly of the colour of the slate, forms ser- 

 pentine veins, which give it the appearance of having been 

 cracked into regular fragments, and cemented bv the lime- 

 stone. When blocks of this slate are exposed to the air, the 

 limestone is easily distinguished, as it decays and forms a brown 

 rotten stone. 



When we become rich enough to indulge in the luxury of 

 <lry roads at those times of the year in which they are now 

 muddy, and of smooth roads at all times, our level roads will 

 be covered with broken slate, of those kinds which readily 

 shiver into thin pieces. The thin flat shingles of slate always 

 incline to rise to the surface if near it : rounded and angular 

 pieces of stone have a tendency to sink. These observations 

 are not founded upon theory: I have seen some small speci- 

 mens of such road. M'Adam, I think, recommends worn- 

 out hoops, and similar useless pieces of iron, for making roads 

 firm in moist situations. Nature has furnished us with a 

 similar material in abundance. The common conglome- 

 rate, with a mixture of rusty slate gravel, will, in moist si- 

 tuations, make a very firm road. I have seen a road made 

 across a small swamp, by first covering the remains of the 

 old pickets with a layer of 10 in. or 12 in. of stone, which was 

 again covered about 10 in. in depth with a rusty slate- gravelly 

 earth, mixed with about a third part of fragments of common 

 conglomerate. For ten years this road, though considerably 

 travelled, scarcely showed the impression of a wheel ; and it is 

 still a tolerable road, though it has not been repaired for twenty 

 years. 



Besides the slates already noticed, there is another kind, 

 always connected with the whinstone, of which it seems to be 

 a variety : it is of a pale colour, never contains pyrites, and 

 is, consequently, never of a rusty colour : it may be cleft like 



