108 THE TRENTHAM GRAVEL BEDS. 



of these impressions we shall find that they are mere 

 surface markings, and have every appearance of being due 

 to pressure or the grinding action of one pebble against 

 another after consolidation. But if pressure or concussion 

 be the cause, how may we account for the forces by 

 which they were produced ? Were those forces applied 

 from above or below? If there were any difference in 

 the size or character of the spots if they became smaller 

 or weaker as we go downwards in the section we should 

 perhaps be led to think that the producing cause was 

 directed from above ; or if the spots became larger and 

 more distinct at the base of the section we might be in- 

 clined to the opinion that the seat of the movement was 

 down deep in the crust of the earth ; but in reality there 

 is no difference in the markings of pebbles from whatever 

 point they may be taken in the quarry. They are of a 

 uniform character, and this peculiarity holds good in every 

 Bunter gravel bed which has come under my notice in 

 the midland counties. I beg to recommend this peculiarity 

 in the Bunter gravels to the careful consideration of those 

 of our friends who have honoured this meeting, to whom 

 the subject offers inducement for investigation. 



One other point for consideration in connection with these 

 pebble-beds, which is, although not peculiar thereto, at 

 least worth notice. By making a careful search amongst 

 the pebble heaps we shall be able to obtain, particularly 

 from indurated marls, a very interesting series of beautiful 

 dendritic markings. 



At the commencement of my paper I ventured to re- 

 mark that the section before us possessed the whole of 

 the characteristic features appertaining to the Bunter pebble- 

 beds. In this I hope I may be permitted to think I was 



