TOANSACTIONS OF SECTION C. 653 



4. On Local Geological FhotograpJiT/, By Osmund W. Jeffs. 



In this paper tlie author suggests the desirability of taking steps to secure the 

 formation of a collection of photographic views illustrating the geological features- 

 of each county. 



Isolated attempts to record local geological features of importance have been 

 made by several provincial societies, amongst others by the Iieicester Literary and 

 Philosophical Society, Liverpool Geological Society, Belfast Naturalists' Field Club,. 

 Chester Society of Natural Science, the Geological Society of Yorkshire, the 

 Croydon Microscopical and Natural History Society, &c. ; but there is need for some 

 systematic scheme to secure imiformity of action in every district in England. 



This could best be done by the appointment under this Association (which i» 

 in touch with all centres of scientific activity in the United Kingdom) of officers 

 in each county charged with the arrangement of details and superintendence of 

 local photographic surveys in their respective districts. The results obtained 

 would be duly preserved, recorded, and catalogued by a central officer of the 

 Association, who would give facilities for the purchase and exchange of views. 



It is important that the date, name of photographer, and full descriptive 

 details (accompanied by explanatory sketches when necessary) be attached to 

 every picture taken. The suggestions made in the paper are for consideration, and 

 subject to such modification as may be arranged by the Committee or the Officers- 

 of Section C. 



Photographic records of sections and of other geological features and physio- 

 graphical phenomena are not only invaluable as aids to class-teaching" and 

 geological instruction generally, but they will serve to preserve for future reference 

 the details of many exposures of strata and other important landscape features 

 which in course of time, by natural and other agencies, are in danger of becoming 

 obliterated. 



5. Further Notes on tJie Origin of the Crystalline Schists of Malvern and 

 Anglesey. By Charles Callaway, B.Sc, M.A., F.G.8. 



At the meeting of the Association in 1887 the author noticed that in the 

 Malvern Hills the foliation was zonal. The igneous rocks, as a shear zone was 

 approached, acquired a parallel structure, and where the zone was penetrated by 

 granite veins hornblende was converted into black mica. In Anglesey also some of 

 the schists resulted from the shearing of igneous rocks, and it was suggested as 

 probable that the limestones of the Older Archseans were endogenous deposits 

 derived from the decomposition of the adjacent rocks. 



Subsequent work in the field and cabinet confirmed and enlarged the above 

 results. At Malvern some new shear zones were examined. At one locality 

 diorite interlaced with vertical granite-veins passed, within the breadth of a yard, 

 into a banded gneiss, with a dip of 70°. Eoth granite and diorite exhibited pro- 

 gressive shearing and mineral change. The granite (binary) passed through the 

 usual stages into muscovite gneiss. These seams were interbanded with a dark 

 schist, consisting mainly of hornblende crystals flattened out, white mica and 

 black mica. 



A large series of observations showed that when a complex of granite and 

 diorite was sheared, mica was produced in both. In the diorite either biotite was 

 formed from the hornblende, or muscovite replaced soda-lime felspar. Sometimes 

 both micas were generated in the diorite. 



Injection schists were sometimes formed by infiltration. Granite and diorite 

 were in contact. Shearing was progressive towards the granite and into it. The- 

 diorite near the junction went largely to chlorite and iron-oxide. These passed 

 into the cracks of the crushed granite, and as the latter was progressively sheared 

 they retained their place between the folia of quartz and felspar. Thus a chlorite 

 gneiss was formed. Black mica was sometimes generated in the chlorite, especially 

 round opaque dots (? iron-oxide). 



The mica (? sericite) schist of the western spur of Ragged Stone Hill was formed 



