THE 



GEOLOGICAL MAGAZINE. 



No. LXXVIII.— DECEMBER, 1870. 



I. — ^NoTES ON Earthquakes. 

 Communicated by the President of the Geological Society of London. 

 Sib, — I beg to send you a notice, seemingly made with much care, 

 respecting the origin and occurrences of earthquakes in England, 

 which I find among some MSS. of an ancestor of mine, who, towards 

 the end of last century, was an active Fellow of the Society of Anti- 

 quaries. It is curious as a record of the crude notions on volcanic 

 phenomena prevalent to so near our times, and may be of some 

 interest as a list — albeit imperfect — of the numerous earthquakes 

 noted in a country where earthquake-movements are exceptional 

 occurrences, and as a record of some peculiar phenomena which, 

 notwithstanding the quaint and pretentious narration, have con- 

 siderable geological interest. According to this record, the earth- 

 quakes were distributed as under by centuries and seasons. 



January 2. 



February 3. 



March 2. 



April 4. "Winter montlis . 11. 



May 5. 



June 0. Spring 11. 



July 3. 



August 4. Summer 7. 



September ... 6. 



— October 1. Autumn 8. 



Total 59. November ... 1. 



— ■ December 6. 



This shows a great prevalence of earthquakes in the 12th century, 

 a gradual decrease in numbers to the 15th, and then a gradual in- 

 crease to the 18th century. They seem also to have been more 

 numerous in winter and spring than in summer and autumn. The 

 months, however, in many cases are not recorded, and no doubt the 

 general record is confined to the more important and noticeable 

 catastrophes. Joseph Pkestwich, 



President Geological Society of London. 



OP earthquakes, by me, sib JOHN PRESTWICH, BART. 



Written apparently about the year 1798. 



The efficient or natural causes of all Earthquakes may be reduced 

 under four general heads, viz.. Efficient, Material, Formal, and 

 Final. The first proceeds from the heat of the sun, which, by its 

 continued heat, and dry weather, cracks the earth in such manner 



TOL. Tll. — NO. LXITIII. 35 



lltll 



Century, 6. 



12tli 





16. 



13th 





6. 



14th 





3. 



15th 





1. 



16th 





5. 



17th 





9. 



18th 



51 



13. 



