Mineralogy and Geology of Nova Scotia. 589 



ironstone slate, a singular variety, of which the distinguishing 

 marks are, that it is heavier than any other stone in the pro- 

 vince: that it is harder than common slate, and some portions 

 of it harder than granite ; and that it generally contains a large 

 proportion of small oval grains, so exactly resembling the 

 gravel formed from the debris of coral rock in figure and size, 

 that I have conceived it to have been originally a shell gravel 

 like that of Bermuda, Florida, &c, which had, since it was 

 embedded in its present position, by the introduction of a por- 

 tion of the iron and hornblende of the rock, changed its colour, 

 and, in some degree, its nature, without losing its original 

 figure. Although, from its resemblance to the stone in which it 

 is embedded, it is scarcely perceptible in some specimens when 

 first broken, yet it is often perfectly visible upon the surfaces 

 of the same specimens ; for, as it frequently decays when ex- 

 posed to the air, either with greater or less rapidity than the 

 stone in which it is contained, the surfaces will sometimes ap- 

 pear eroded with small oval cavities, while in other specimens 

 they are overspread with the gravel in the form of the roe of 

 fishes. % 



The hardest and heaviest ironstone is frequently separated 

 into flags, which show no disposition to separate again. It 

 rings like metal when struck, and contains abundance of 

 small crystalsof hornblende, extremely hard, branching through 

 in every direction. It is very dark-coloured, and has the smell 

 of hornblende: perhaps it ought to be called a hornblende 

 slate. I have observed that where the west end of the whin- 

 stone joins the granite, it differs little from the ironstone, be- 

 coming heavier than common whin, and containing coral gravel. 

 In the few places where I have seen the rock naked at the 

 line of junction, the ironstone appears to dip under the granite ; 

 and, although I have seen hundreds of fragments of ironstone 

 embedded in granite, I have not as yet met with a piece of 

 granite. in ironstone. 



These embedded fragments form so large a proportion of 

 the rocks near the shore, that the sand between Sambro and 

 Margaret's Bay has a grey colour ; and the persons who supply 

 Halilax with white sand find it necessary to go farther west- 

 ward. The islands opposite the southern shore of the town- 

 ship are granite rocks. Their southern sides, exposed to 

 the open sea, are worn always, and show layers of fine-grained 

 stone (apparently formed from fine granite gravel), mixed 

 with common black shorl. These layers are usually about 

 1 ft. in thickness, and, like those of stratified gravel, form 

 curves somewhat analogous to those of the hill above them. 



Is it not probable that this rock is of later formation than 



