244 PROCEEDINGS OF THE COTTESWOLD CLUB 



" standpoint, was brilliantly successful in another light. 

 " The bearing and box, both of drop-forged steel, were 

 " welded to each other, and broke into a dozen pieces. The 

 " interesting j)oint, however, was the fact that two forgings 

 " of laminated steel under the agency of heat were con- 

 " verted to a metamorphic form. At the surface of welding, 

 " the laminated steel became crystalline, and even the parts 

 " at some distance became semi-crystalline. It was a fair 

 " illustration of what is now called ' dynamo-metamorph- 

 " ' ism.' " The writer then goes on to compare the 

 metamorphism of the steel under the influence of pressure 

 and heat, with the metamorphism of the Malvern rocks 

 as described in my memoirs, and he concludes that " in 

 essential principles " the metamorphism in both cases is 

 of the same kind. With this view I agree, and I point 

 the moral of Dr. Redway's illustration by asking : If the 

 forces developed in a steam-engine can do so much in 

 such a substance as steel, how much more may be effected 

 by enormous earth-pressures acting upon stone, which, 

 compared with steel, is soft and friable ? 



That heat was generated during the metamorphism of 

 the Malvern crystallines, can be demonstrated by the 

 direct observation of microscopic slides. The fragments 

 produced Ijy the crushing are seen in an advanced stage 

 of the schist-making to lose their angularity, and to be 

 flattened out into minute cakes. These are often cement- 

 ed together to form larger cakes or lenticles. In the 

 completed gneiss, the fragmental structure is often entirely 

 lost, but sometimes there remain a few crushed crystals of 

 felspar to indicate, like an ill-cooked potato in Irish stew, 

 the origin of the rock. 



There will be little ditflcuhy in understanding that all 

 this crushing and shearing has been attended by great 

 chemical changes. In the earlier stages, decomposition 

 sets in ; in a later stage, reconstruction occurs. Complex 



