Mineralogy and Geology of a part of Nova Scotia. 307 



order, the rock formations and the minerals occurring in 

 them. We did not examine Briers' Island, but from a de- 

 scription of it by its inhabitants, we have no doubt of its be- 

 ing similar to Long Island, which is composed of columnar 

 greenstone, almost to the exclusion of every other rock. 

 The greenstone is somewhat irregular in its columnar struc- 

 ture, not exhibiting that regular prismatic form which we 

 shall hereafter notice, as occurring at some other places. It 

 is of a darker color, and difficultly acted upon by the causes 

 of decay, so that the Island exhibits but a comparatively 

 thin soil, but sufficient to reward the labors of the husband- 

 man. Few minerals of interest occur at this place ; they 

 are mostly such as we shall have occasion to notice as oc- 

 curring, more abundantly, in other districts of the north 

 Mountain range. They are veins of jasper, chalcedony and 

 a little amethyst. At low water the amygdaloid, on which 

 the columnar greenstone rests, is accessible ; in which oc- 

 curs chlorite, filling the cavities in this rock. Indeed this 

 mineral prevails here, to the exclusion of the zeolite, which, 

 as we shall hereafter show, more generally occurs. It pre- 

 vails in nodules, filling the spheroidal cavities in the amygda- 

 loid ; when broken, it presents laminae, of a beautiful leek 

 green color, radiating from a centre, and rarely crystallized 

 in low tabular crystals, often intersecting each other. It is 

 soft, easily scratched with the finger nail — is somewhat unc- 

 tuous to the touch and has an argillaceous odour when 

 moistened — before the blow-pipe it melts into a black scoria. 

 The chlorite has often been removed by external causes, 

 thus imparting to the rook a vesicular appearance ; but in 

 some few cases, the cavities were naturally left void, consti- 

 tuting the real vesicular amygdaloidal trap. 



The veins of jasper, as they traverse the amygdaloid, be- 

 come singularly altered in their character, being converted 

 into a substance resembling, in appearance, imperfectly burn- 

 ed bricks of potters clay. The specimens from the interior 

 of the vein, where it had not been acted upon by exposure, 

 presented the same appearance ; some parts were in fact per- 

 fect clay stone. — As the veins entered the superincumbent 

 columnar trap, they became altered in appearance, and in 

 the course of a few yards, became converted into a very per- 

 fect red jasper. Three or four veins of this character were 

 observed, which all presented similar appearances. 



How did the columnar trap convert these veins of clay 

 stone, if they may be so called, into jasper ? We leave thos 



