Remarks on Miner alocjical Classification. 33 



tirely composed of trilobites or small fossil shells, while 

 others, which have been used for the distillation of paraffin 

 oil, lie immediately above richly organic limestone beds. 

 The classification which would make shale and coal im- 

 perceptibly merge into one another, mainly because of a 

 chemical similarity, is in my opinion clearly erroneous. 



Might not the organised structure visible in certain rocks 

 be employed as a distinctive feature in arranging this order? 

 We would have little difficulty in distinguishing two great 

 classes of rocks and minerals : first, those indubitably 

 showing by the microscope their organic texture ; and, 

 secondly, those which, while they do not exhibit microscopic 

 structure, yet clearly indicate, by their chemical composi- 

 tion, a secondary organic derivation. We might thus create 

 one great order, and as important a sub-order. The order 

 would include the limestones and the various varieties of 

 coal, including peat, anthracite, cannel coal. The sub-order 

 would comprise the bitumens, ambers, &c. ; in short, with 

 the exception of sulphur, all the genera included in the 

 seventh order. The species and varieties of bitumens and 

 resins would thus be more easily capable of specific sub- 

 division. The animal or vegetable origin of the bitumen 

 family might tlius be left open, and shales would not be 

 confounded with coal. The bringing together of two such 

 apparently different bodies as limestone and coal is merely 

 a popular objection to our general proposal. By following 

 the path of inductive science, light might be obtained on 

 many dark questions in petrology. As a sample, the micro- 

 scopist now detects bituminous globules in rock crystal ; 

 let him apply his art to calc-spar and the conjoined families, 

 and what curious resemblances to minerals, from which 

 they are apparently very different, may he not discover ? 



We might, too, relegate into a distinct class the Torbane- 

 hill mineral, the Albertite of Pictou, and the mineral of St 

 John's, N. B., — bituminous substances the true nature of 

 which has been the cause of so much discussion amongst 

 scientific men. In the opinion of many most competent 

 observers, these minerals exhibit no microscopic structure 

 similar to coal ; while several able chemists affirm that their 



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