248 QUAKTZ IN COAL. 



equal power, or else one of them is superior to the other. It thence follows that the greater 

 number of these morpfiolites, in consequence of the predominating influence of the linear 

 direction of development, appear egg-shaped, or pisiform, or owing to the concentric 

 direction prevailing, or the two forces being equal, assume the shape of discs or spheres, 

 or are in an intermediate condition." Ehrenberg calls these bodies Crystalloids, or Mor- 

 pholites. In Scotland they are called Fairy Stones. 



ORIGIN OF QUARTZ FRAGMENTS IN THE COAL. 



One fact, briefly alluded to in the preceding account of the Brandon Brown Coal, de- 

 serves further elucidation. This coal is in general remarkably free from the admixture 

 of foreign substances, except that small grains of pure hyaline quartz are disseminated 

 through almost the whole of it. They vary in size from bits a quarter or even a half of 

 an inch across, to those so small that a microscope is needed to see them. They are not 

 rounded like grains of sand, but look like crystallized quartz that has been crushed into 

 fragments, though in a few cases they have the appearance of having been subject to some 

 attrition. They are more abundant in some places than in others, but never lie crowded 

 together like a mass of sand or gravel. 



We are exceedingly puzzled to give any satisfactory explanation of these facts. We 

 suggest three hypotheses, but neither of them satisfies us. 



1. We may suppose that the currents of water that accumulated the vegetable matter, 

 brought along also the fragments of quartz and diffused them through the peat. But why 

 are not fragments of other rocks mixed with the quartz ? I have in one instance seen a 

 minute fragment of talcoid slate, but this was all among the thousands of angular bits of 

 semi-transparent quartz. It is incredible that currents of water should have made such 

 a selection, running as it did over rocks of various kinds. The quartz corresponds essen- 

 tially to those white tubercular masses met with occasionally in the most thoroughly 

 metamorphosed schists of the State. But how these could have been crushed into such 

 small fragments, and selected from all other sorts of rocks and minerals, seems quite 

 inexplicable. 



2. We might suppose that the water which penetrated the deposit when in a course of 

 formation contained, as the water of clayey deposits often does, a quantity of alkaline 

 silicates, which, by the help of the organic matters, were decomposed and left the silica in 

 the form of these fragments. The great objection to this hypothesis is, that quartz thus 

 originating would not be left in the form of angular fragments, having the appearance of 

 fracture, though the smallest particles might have been thus produced. 



3. We might suppose that the fragments were originally of various kinds, but the 

 alkaline water, with which the mass was permeated, aided by the reactions of the organic 

 matters, dissolved and abstracted all the minerals except quartz. And it must be con- 

 fessed that the grains of quartz often have the aspect of a ruin, or as if something had 

 been abstracted from them, and these were left as an insoluble residuum. Their predom- 

 inant angularity is the chief objection to the hypothesis ; but upon the whole we look 

 upon it as the most plausible of the three. If we had had access to the deposit, since our 

 thoughts have been specially turned to the subject, something more satisfactory might 

 perhaps have been suggested. 



