On Fulgurites from Monte Viso. 205 



tradictory statements and much of the confusion in regard to the 

 origin and significance of foliation are due to the failure to recognize 

 the distinctness of these two structures. In regard to them it may 

 be admitted that sometimes "extremes meet," and a crystalline 

 rock pulverized in situ is very difficult to separate from a greatly 

 squeezed fine-grained sediment ; but he believes these difficulties 

 to be very local, probably only of a temporary character, and of 

 little value for inductive purposes. 



2. " On Fulgurites from Monte Viso." By Frank Rutley, Esq., 

 F.G.S., Lecturer on Mineralogy in the Royal School of Mines. 



The specimens described in this paper were collected by Mr. 

 James Eccles, F.G.S., close to the summit of Monte Viso (12,680 

 feet above sea- level). They are fragments of a glaucophane-epidote 

 schist, in which garnet, sphene, and occasionally diallage are pre- 

 sent. Prof. Judd considers that the rock somewhat closely resembles 

 the glaucophane schists and eclogites of the He de Groix. 



The fragments are bounded by joint-planes or surfaces of easy 

 fission, which are incrusted with minute pellets and thin films of 

 fulgurite-glass forming the walls of lightning tubes. The glass was 

 examined under the microscope (great care being taken to insure 

 perfect isolation of the glass from the rest of the rock), and found 

 to be, as a rule, remarkably pure, but in places not only gas-bubbles 

 but also globulites occur, and the latter occasionally form longulites, 

 and more rarely margarites. Microliths also are observable in some 

 of the sections. In one section a minute rounded grain of schist 

 containing a fragment of a strongly depolarizing crj^stal, probably 

 epidote, appears to have been taken up in the glass. 



Where the glass comes in contact with the rock the latter appears 

 to have undergone no alteration beyond the development of a very 

 narrow band of opaque white matter, which the author gave reasons 

 for supposing to be due, not to the action of the lightning, but to a 

 pre-existent segregation of sphene. 



The occurrence of globulites, margarites, longulites, and micro- 

 liths in the glass would seem to indicate a less sudden cooling than 

 is assumed to be usual in such cases ; for the glass presents no signs 

 which would characterize a subsequent devitrification or secondary 

 change, and the bodies just enumerated appear, unquestionably, to 

 have been formed during the refrigeration of the fulgurite. 



3. " On the occurrence of a new form of Tachylyte in association 

 with the Gabbro of Carrock Fell, in the Lake District." By T. T. 

 Groom, Esq. 



In this paper the author described an ancient but well-preserved 

 glassy rock of basic composition which he had found as a vein 

 associated with the gabbro of Carrock Fell. The rock was described 

 macroscopically and microscopically, and a complete chemical ana- 

 lysis was given. The chemical composition resembled that of the 

 more acid basalts and the augite-andesites, and approached especially 

 closely to some continental basalts, analyses of which were added 

 for comparison. Examined microscopically, the rock consisted of a 



