120 Prof. Hughes, On some Chipped Flints from [Mar. 9, 



produce results upon the great table-lands and protuberant masses 

 analogous to what are called " marginal effects " in earthquakes ; 

 which might explain what are called overthrusts, that is, nearly 

 horizontal slides of masses of rock; it may be where the friction has 

 been reduced by the liquefication of deep-seated strata when the' 

 pressure is relieved by the pull, or it may be where there already 

 existed molten lakes below, or where fractured and lubricated 

 divisional planes occur in the solid rock. 



It is a matter of observation that such movements have taken 

 place. Can they be explained by any well-supported theory of 

 earth movements which shall be consistent with all the other 

 operations which we know have been going on ? 



If astronomers and physicists would account for the observed 

 periodicity of earth movements by allowing the sun and moon to 

 pull the trigger when denudation and deposition with secondary 

 internal changes have loaded the gun they would be speculating 

 along lines suggested by observation from many different points of 

 view. 



(4) On some Chipped Flints from the Plateau Gravel of 

 Salisbury and elsewhere. By Prof. T. McKenny Hughes, M.A., 

 F.R.S. 



It has long been an accepted fact that flints showing traces 

 of man's handiwork are found in river gravels which from their 

 relation to the physical geography of the district and by the 

 shells and bones found in them are referred to a very remote 

 antiquity. These implements are connected by similarity of 

 form and by the associated remains with others which have been 

 found in caves, where a much larger and more varied assortment 

 of remains of human art and appliances have led to the inference 

 that the man of that period was not at all low down in the scale 

 of civilization but might be compared rather to the Esquimaux of 

 to-day. 



Seeing therefore that the earliest men of whom we know any- 

 thing for certain do not exhibit characters pointing to a low stage 

 of development, we are always looking out for traces of some still 

 earlier race. Many a time has the discovery been announced and 

 primaeval man been referred further and further back until some 

 have even assigned a place in this hierarchy to "man's pre- 

 cursors." 



I would invite the attention of the Society this evening to the 

 evidence which has been recently brought forward in support 

 of the view that among the flints and in the patches of gravel 

 which occur scattered, both over the beds which rise from below 

 the chalk, and over Tertiary beds which rest on the chalk, as 

 well as over the chalk hills themselves, we have evidence of man's 



