Description and Analysis of Gurolite, a new Mineral Species. Ill 



pling of streams and the sound of breakers appear to be almost 

 exclusively due. I have examined a stream or two, and in all 

 cases where a ripple made itself heard I have discovered biibbles. 

 The impact of water against water is a comparatively subordinate 

 cause, and could never of itself occasion the murmur of a brook 

 or the musical roar of the ocean. It is the same as regards 

 waterfalls. Were Niagara continuous and without lateral vibra- 

 tion, it would be as silent as a cataract of ice. It is possible, I 

 believe, to get behind the descending water at one place ; and if 

 the attention of travellers were directed to the subject, the mass 

 might perhaps be seen through. For in all probability it also 

 has its 'contracted sections,' after passing which it is broken 

 into detached masses, which, plunging successively upon the air- 

 bladders formed by their precursors, suddenly liberate their con- 

 tents and thus create the thunder of the waterfall. 



XV. Description and Analysis of Gurolite, a new Mineral Species. 

 By Thomas Anderson, M.D., F.R.S.E., Lecturer on Che- 

 mistry, Edinburgh^. 



THE mineral described in the following pages I first saw in 

 the hands of a mineral-dealei', who offered it for sale under 

 the name of Herschelite. A very cursory examination enabled 

 me to see that it was not that mineral, and led me to the con- 

 clusion that it was either pectolite or a new species ; and a few 

 preliminary trials appeared rather to confirm the latter opinion, 

 but my specimen was not sufficiently large to enable me to svib- 

 mit it to accurate analysis. In the autumn of 1849, hov/ever, I 

 paid a visit to Skye, where I found the mineral, not abundantly, 

 but in sufficient quantity to enable me to examine and analyse 

 it. I then found that what I had before seen were weathered 

 and effloresced specimens ; and the result of my examination 

 proved it to be a new and very distinct species, to which I give 

 the name of Gurolite (from 711/30?, orhiculatus), from the peculiar 

 form of its crystalline concretions. 



Gurolite occurs at Storr, about nine miles from Portree, at the 

 spot already so well known to mineralogists for the abundance 

 and beauty of the specimens of apophyllite, stilbite, laumonite, 

 and other zeolites found there. With these gurolite occvu'S 

 associated, and it is sometimes found coating crystals of apo- 

 phyllite. The best and finest s])ecimens, however, are not found 

 in immediate contact with these minerals, but arc met with in a 

 basalt of very different characters from that in which they are 



* Communicated by tlic Autlior, liiiving been read before the Royal 

 Society of Edinburgh. 



