Lieut. Baddeley on Sulphate of Strontiati^ ^c\ 107 



in question when fused on charcoal, although I should conceive there 

 can be no doubt that it is a sulphate of strontian. 



This mineral is associated with calcareous spar, generally flesh- 

 colored ; often with the sulphuret of iron, (arsenical ?) occasionally 

 with the sulphuret of zinc, (black, and more rarely yellow, blende.) 

 Two or more of these minerals form rounded concretions in hori- 

 zontal limestone, and vary from the size of a small potatoe to that of 

 a large cocoanut.* 



The limestone is of a bluish grey color, a compact and uncrystalline 

 structure, and is slightly translucent on the edges. Its odor, when 

 struck, is like that produced by siliceous matter, and it appears to be 

 entirely destitute of organic remains, hke most of the limestones of 

 Kingston, which exhibit distinct traces of these natural antiquarian 

 remains only among the uppermost strata, while the lowermost rest 

 upon a crystalline rock, which is here an aggregate composed of 

 felspar and quartz, and there an aggregate composed of felspar 

 and hornblende, the one and the other occasionally seamed and 

 studded with schorl and epidote. The geological fact which at- 

 tracts the most notice here, is the conglomerated character of the 

 limestone in contact with this crystalline rock, which appears some- 

 times to be a granite, (though mica is rarely present) sometimes a 

 syenite, and sometimes a greenstone or trap. 



This conglomeration, in some cases, consists merely of round- 

 ed pebbles of quartz inserted into the limestone ', in other cases, the 

 intrusion is of a much more violent character, when large masses of 

 the aggregate itself, both rounded and angular, appear detached 

 from the parent stock, and lie insulated and enveloped by the lime- 

 stone. In ordinary cases, the limestone appears always to adapt it- 

 self to the surface of the rock which it overlies. 



I have said, that organic remains appear to be confined to the up- 

 permost strata of limestone, and that the lowermost strata are entire- 

 ly destitute of them. However near this may be to the fact, it is 

 not exactly so. Capt. Bonnycastle, R. E., has a specimen, in which 

 is the distinct impression of a shell (terebratula ?) at the line of junc- 

 tion of the limestone and granite, (felspar and quartz.) 



In many specimens the union of the two rocks is very intimate, 

 and although in all cases you may trace the line of separation, yet 



* A rounded mass, composed entirely of strontian, found detached on the north 

 shore of Lake Ontario, near Kingston, and now in my possession, weighs about 

 ten pounds. 



