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DESCRIPTIVE CATALOGUE 



74. Greenstone — fine-grained; minutely crystalline; compact; colour, black. 

 Has the general aspect of basalt. 



75. Undetermined. A trappous-looking cellular rock ; the joints and cells filled 

 with zeolites. Probably a metamorphosed shale. 



76. Metamorphosed sandstone — the rounded grains of quartz distinctly visible ; 

 colour, red in some places, dark reddish gray in others. Resembles the quartzites 

 of Wisconsin and Black Rivers. An undetermined green magnesian mineral is 

 disseminated through it, in grains and in cells. 



77. Same as No. 76, from which it is separated by some thin seams of finely 

 laminated siliceous material. Contains large nodules of calcareous spar. These 

 two last-named rocks resemble the volcanic grits, and appear to contain a large pro- 

 portion of volcanic material. The difference in colour depends on the amount of 

 iron in different specimens, and its state of oxidation. 



78. Metamorphosed shale — amygdaloidal ; many of the cells empty, others filled 

 with laumonite ; colour, purple. Shows every evidence of fusion. 



79. 80, 81, 82, 83. Metamorphosed sandstone — some of the specimens scarcely 

 altered, others highly metamorphosed, and hardly to be distinguished from trap. 

 In near contact with the next rock becomes amygdaloidal, the cells being filled, 

 principally, with nodules of calcareous spar, which are surrounded with a thin film 

 of chlorite (?). 



84. Basaltic trap — in contact with the metamorphosed rock. 



85. Basalt. Resembles, precisely, some of the Bohemian basalts, particularly that 

 from Aussig. 



86. Metamorphosed sedimentary rock. Bears some resemblance to No. 67. This 

 is probably a fine trap breccia, cemented by siliceous matter, which has been so 

 acted upon by heat as to give it the aspect of quartzite. 



87. Jasperoid rock — the joints encrusted with zeolites. 



88. Metamorphosed sandstone. 



89. Metamorphosed sandstone — amygdaloidal; cells filled with calcareous spar. 

 Less altered than No. 88, and more argillaceous. 



90. Metamorphosed siliceous shale — with numerous yellow spots, which penetrate 

 the layers vertically ; with wide yellow stripes near the weathering edges. At the 

 partings, exhibits many minute grains of hornblende. Some of the beds are argil- 

 laceous. 



91. Breccia — cemented by siliceo-argillaceous matter, and burnt into a jasperoid 

 rock. Colour, red ; porphyritic. Resembles No. 86. 



92. Basaltic greenstone — minutely crystalline ; colour, grayish black ; columnar. 



93. Same as No. 91. Less altered by heat; some of the layers have stripes of a 

 light pink colour. Contains some few water-worn siliceous pebbles. The breccia 

 with which this is connected contains numerous fragments of slate. Some of the 

 beds might, in hand specimens, be called " wacke." 



94. Metamorphosed volcanic grit — has grains of a green mineral disseminated 

 through it. Resembles Nos. 90 and 91, but is less quartzose. 



95. Volcanic grit — contains felspar, quartz, and hornblende, in grains. It is 

 somewhat syenitic in appearance, but is much less crystalline than syenite. It 



