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their cleavage faces numerous interesting weathered fossils of 

 the less delicate kinds, such as large Belemnites, Pedens, and 

 PUcatulce, whichwill be referred to under the section Palseontology 

 of the zone. It will suf&ce to remark that the predominant 

 lithological character of the Sandstone of the Spinatus zone is 

 instability. We now pass fi'om the superficial appearance of 

 the rock, and glance at its embedded lithological contents, such 

 as nodules, rock fragments, and concretions. INone of these 

 occur in definite horizontal bands or courses, but are scattered 

 irregularly throughout the mass of the rock. The most 

 remarkable and conspicuous of them, consist of small pieces of 

 dark gray green rock occasionally met with in the light yellow 

 coloured sands. In size they do not generally exceed two or three 

 inches in length, and are rough fragments of irregular shape, 

 much as though struck from the rock by a sharp blow, and are 

 neither water-worn nor abraded. These dark green pieces of 

 rock are of considerable lithological interest. They are doubtless 

 portions of a derived rock, and are thus remanie, that is, worked 

 up again. There was at first some ground for supposing these 

 pieces to have been derived from rocks older than those of 

 liassic age ; but a more careful examination and rigid testing 

 forces on us the conclusion that their origin was from older 

 Middle Lias rocks, perhaps breakers in a bay, splintered up and 

 washed into the sands by the violent action of a battering 

 ground swell, such as I have oftened witnessed on the iron-bound 

 coast of Brittany and North West France. Now, were these 

 pieces of old rock more abundant, and also cemented together 

 by a siliceous or calcareous medium, instead of lying loosely 

 scattered through the mass as they do, we should properly assign 

 to them the designation of a breccia. Their occurrence, anyhow, 

 is peculiar, and I will distinguish them by giving an account of 

 their chemical examination by an experienced physicist of our 

 Society, Mr. E. Holland. Their colour is to some extent due to 

 manganic silicate and the dark green hue of the underlying 

 beds {Margaritatus Zone) is due to the same mineral. Mr. 

 Holland at my request, tested these rocks for manganic oxide 

 by means of the spectroscope. He writes " I found a faint 



