232 



DESCRIPTIVE 



CATALOGUE 



contained fragments, but appears to be derived from the same rock ground to 

 powder. 



202. Siliceo-argillaceous shale — highly metamorphosed ; prevailing colour, that of 

 well-burnt clay, with yellowish bands, stripes, and spots. The spots, which are 

 oval, are disposed in somewhat regular lines, and connected at their long diameters 

 by very thin lines, which seem to pass through the centres of the spots, and to 

 have been cracks, through which the discolouring agent found its way. The spots 

 pass vertically through the beds. The rock is very thinly laminated ; colour of the 

 lamina 1 , gray, orange, yellow, and red, giving to the edges of the bed a riband-like 

 appearance. Contains small segregations of quartz and of calcareous spar between 

 the laminae, which are bent around these lumps. At the joints, the rock is dis- 

 coloured from half an inch to four inches in width. The lighter-coloured laminse, 

 most of which are very thin, seem to be composed of quartz-sand almost entirely, 

 while the red ones are argillaceous. This rock resembles, in all respects, the base 

 of the " Great Palisades," except in not being porphyritic. 



203. Siliceo-argillaceous shale — thinly laminated ; highly metamorphosed ; colour,' 

 light yellow, with thin bluish bands. Over fifty lamina3 may be counted in the 

 depth of an inch. 



204. Volcanic grit — amygdaloidal ; colour, reddish gray; coarsely granular; very 

 ferruginous; contains many grains of thalite. 



205. Alternations of volcanic grit and fine breccia — anrygdaloidal ; contains some 

 water-worn pebbles. Full of zeolites, and carbonate of lime in grains. Colour, 

 light red. 



200. Volcanic grit (?) — resembles the metamorphosed earthy sand-rocks ; amyg- 

 daloidal ; fine-grained ; colour, dark red. 



207. Metamorphosed grit — amygdaloid ; fine-grained ; ferruginous. 



208. Basaltic rock — very fine-grained; homogeneous; colour, greenish gray; 

 numerous irregular accidental joints, both horizontal and perpendicular, seemingly 

 produced by a force acting from below, sufficient to fracture the rock, but not to 

 break it up. These joints are encrusted, all of them, by deep-red stilbite, which 

 gives to a hand specimen, separated at the joints, an almost totally red appearance. 

 In consequence of this rock fracturing most easily at the joints, specimens of any 

 size present an exceedingly fragmentary appearance, not unlike many of the 

 breccias, where the fragments are much harder than the cement. 



209. Siliceo-argillaceous matter, minutely granular, and amygdaloidal; brick-red 

 colour ; and containing carbonate of lime in small grains. Traverses No. 208, and 

 the metamorphosed rocks, in veins. 



210. Veins in No. 208, and the associated rocks. Contains zeolites, calcareous 

 spar, thalite, and fragments of shaly amygdaloid. 



211. Metamorphosed siliceo-argillaceous shale very porphyritic, with decomposing 

 crystals of felspar. These beds contain a very fine-grained, dark purplish-gray, 

 basaltic stratum, which is represented by one of the specimens marked No. 211. 



212. An aggregate of gravel-stones, small pebbles, and sand, with a great many 

 small pyramidal crystals of quartz ; lumps of flesh-coloured felspar, zeolites, and 



