26 



Davison : Yorkshire EartJiquakes. 



tracing the contour line, commencing at tlie narrowest point 

 below the body and going downwards, the line gradually swells 

 outwards and then inwards, forming a convexity. It next forms 

 a shallow concavity, and expanding slightly forms the rounded 

 external corner of the tail ; again passing downwards and 

 inwards towards the central line, it forms a bold rounded pro- 

 jection, and ends in a deep notch in the central line of the tail 

 end ; the other side and half the end is formed in the same 

 manner. Tracing the outline in the same way in Fig. 2, it 

 will be observed that after the first convexit}- there is another 

 and smaller one before the external corner of the tail is reached ; 

 the end contour line of the tail also crosses directly from one 

 side to the other in a wavy line, the convexities and concavities 

 being much less marked tiian in Fig. i, the central notch 

 being comparatively shallow. Also the markings on the surface 

 of the tail of the two mites are not alike. I am of opinion that 

 this is a new and undescribed species, and have given it the 

 name insperatiis, i.e., the unexpected. 



I also wish to add to my list of Lincolnshire Hydrachinda; — 

 Arrhenurus nodosus Koenike and A. stecki Koenike. 



YORKSHIRE EARTHQUAKES. 



CHARLES DAVISON, Sc.D.. F.G.S., 



Birmingham. 



During the last 16 years I have been engaged in studying the 

 earthquakes of England, the results of m}^ work being contained 

 in papers published in the ' Quarterly Journal of the Geological 

 Society,' the ' Geological Magazine,' and in my report on the 

 'Hereford Earthquake of 17th December 1896.' I propose now 

 to carry the work backwards so as to prepare as complete a 

 history of British earthquakes as may be possible at the present 

 day. To do this at all satisfactorily is of course beyond the 

 powers of one man. It requires access to the files of local 

 newspapers. Records of past shocks may be preserved in 

 private journals, and not a few are to be found in the pages of 

 county histories or loca} magazines. These sources are for the 

 most part inaccessible to all but their owners, and it is therefore 

 only by the kindly aid of others that the necessary materials can 

 be procured. If any readers of 'The Naturalist' should be 

 able and willing to contribute records either from the sources 



Natii ralist. 



