0 F T HE ROCKS 0 F LAKE SUPERIOR 



229 



135. Volcanic grit — ferruginous ; contains a green mineral disseminated through 

 it in grains, and some cavities of considerable size filled with the same. 



136. Fine-grained, reddish-coloured trap. 



137. Basaltic trap — colour, grayish black ; fracture rough, and slightly nodular. 



138. Metamorphosed siliceous shale, like No. 110. 



139. Resembles No. 138, but is more highly metamorphosed. In some beds, 

 could hardly be distinguished from the slaty greenstones. 



140. 141. Volcanic grit and breccia — amygdaloidal in some places, and filled 

 with zeolites ; approaches, in general characteristics, the metamorphosed earthy red 

 layers. 



142. Volcanic tufa — amygdaloidal, cells numerous, very small, principally filled 

 with zeolites ; some of them contain green carbonate of copper. 



143. Greenstone — this is most probably a dolerite, like No. 133. 



144. Volcanic tufa — containing very large crystals of felspar. 



145. Volcanic tula — colour, dark brown; contains a large percentage of hydrated 

 peroxide of iron. 



146. Volcanic grit — colour, purplish gray ; minutely granular; numerous grains 

 of a green mineral disseminated through it. 



147. Metamorphosed earthy red shale — traversed by veins containing apopholite, 

 Heulandite, calcareous spar, and an undetermined magnesian mineral. 



148. Amphodelite rock — highly crystalline ; colour, gray and light pink. On a 

 superficial examination, might be mistaken for crystalline quartz rock. 



149. Greenstone — rather coarse-grained; crystalline; contains much hematite. 

 In some respects, resembles basalt. 



150. Basaltic rock. 



151. Volcanic grit — very amygdaloidal ; contains a great deal of a green magne- 

 sian mineral,* in grains and in cells ; colour, reddish gray. 



152. Dolerite. 



153. Volcanic grit — like No. 151. 



154. Same as No. 151. Some of the cells an inch in diameter, and filled with 

 mesole ; prevailing colour, reddish gray, but acquires a greenish tint in some places, 

 from the large quantity of green mineral disseminated through it in grains. 



155. Volcanic grit — ferruginous; trappous-looking ; filled with grains of " green 

 mineral" (thalite) . Colour, dark gray, with a tinge of green ; in some specimens it 

 pinkish is gray. 



156. Jasper. 



157. Volcanic grit — made up of felspar, hornblende, quartz, and oxide of iron ; 

 minutely granular ; some green mineral disseminated through it. General aspect, 

 dark red, with greenish spots. 



158. Dolerite — dark-coloured; crystalline, the felspar crystals green; numerous 

 small glistening points. 



159. Same as No. 158, but taking on a syenitic appearance. Is made up princi- 

 pally of red felspar, black hornblende, and oxide of iron. 



* Since this Catalogue was written, Dr. D. D. Owen has described the mineral alluded to under the 

 name of Thalite. (See Jour. Acad. Nat. Set. Phil., Vol. II., Part II., 1852.) 



