192 Correspondence — Professor Prestioich, B.C. L. 



and hills as well as mountains alike with great regularity and 

 sharpness, I think I am justified in saying that the hard rocks are 

 also affected by the fault. If diluvial and alluvial deposits were 

 only affected by it, the line must be of only short distance, and may 

 perhaps not be a straight line, but I found the line of fault crossed 

 intervening hills and appeared again on the opposite side, keeping 

 thereby the same direction on either side. The faulting in 

 one case took place in a rocky crust, and must be deep-seated. 

 Unfortunately the fault did not cross the hard, eroded valley bottom 

 where the effect oi friction by shifting might perhaps be observed. 



" The next question is whether the shock was of sudden or pro- 

 longed nature. As there was no sign of change in topography 

 before the last convulsion, the shock must be a sudden one, other- 

 wise houses standing upon the fault-line must have inclined toward 

 one or other side before the shocks, which was not the case, at any 

 rate I have heard of no such signs when going through earthquake- 

 districts when I had opportunity to converse with the unhappy 

 people. I think the faulting, which produced the last catastrophe, 

 was what the miners call leave, or hlatt of German geologists, 

 i.e. the fault crossing the strike of strata complex. If the solid 

 large mass of crust had suddenly shifted, as I think was the case in 

 the^'earthquake of Japan 1891, a great amount of friction must have 

 occurred along the plane of fault, and thereby, mechanically, heat 

 may have been developed which may have melted the rock or 

 produced slicken-side on the cheeks of bounding rocks. _ I regret 

 much that I made no observations in this direction. Till now I 

 have not heard of any new appearances of hot springs in faulted 

 district. In every textbook on geology it is stated during mountain- 

 making process faults are produced by which rock-masses slide along 

 the dislodged plane, thereby partially melting the neighbouring rocks 

 by the development of mechanical heat by friction, and convert a 

 rock into another form and producing regional metamorphism. 

 In the last sudden faulting no such changes were observed by me. 

 Such phenomena might occur in the deeper parts of the earth-crust, 

 but near the earth-surface, so far as I know, nothing resembling 

 such phenomena was observed or recorded by any person." 



Allow me to observe in reply to Mr. Hill's courteous letter that 

 I do not take the great fault at all as a measure of the forces to be 

 dealt with, but merely as an indication of their nature, and not as 

 evidence of their degree, which can only be judged of by the results 

 in each particular case of disturbance. 



Shobeham, Kent. JosepH PrestwioH. 



\mh March, 1894. 



William Pengelly, F.K.S., F.G.S.— With deep regret we record 

 the death of this well-known geologist, who has done so much during the 

 past forty years in the exploration of Brixham Cave, and Kent's Cavern, 

 Torquay • in the establishment of the Devonshire Association for the 

 Advancement of Science, and the Torquay Natural History Society. He 

 died at Torquay on iVth March, in his 83rd year. We hope to give 

 an Obituary Notice of Mr. Pengelly next month. 



