Dr. C. A. Matley — Bunter Pebhle-beds in Midlands. 211 



mounds a few feet above the flood-levels ; the older, which occupies 

 terraces about 20 feet higher and fringe the vale at Beeston, Gamston, 

 and elsewhere. The ploughed fields and gravel-pits situated on these 

 terraces all yield facetted and other types of wind-worn stones, but 

 though the surface of the younger gravels have been carefully searched, 

 not a single one has been found. It seems, therefore, that for a while 

 the Trent, probably ruuch swollen by the melting snows and ice of 

 late Pleistocene times, cut out its trench-like valley with great 

 rapidity, but that when it reached the level of the older gravel 

 terraces it paused in the process. During this long pause climatic 

 conditions were such as to favour effective wind-action. Subsequently 

 the river deepened its vale a little more, but since that time this 

 action has been reduced to a minimum. 



EXPLANATION OF PLATE XVI. 



Fig. 1. View of the Arnot Hill sewer trench. The boundary between the clay 

 and the thickest part of the dreikanter-bearing gravels is indicated 

 by the top of the workman's tool. 



,, 2. Wind-swept surface of Bunter. Top right-hand portion shows the 

 projecting and loose pebbles. On the left, and below, some clay 

 is seen still adhering to the surface and surrounding the projecting 

 pebbles. 



,, 3. Facetted stones. Those marked a, b, c, d, e were collected from 

 various points on the sheet of gravelly drift. Those marked 

 /, g, h, i were collected from the Triassic ' dreikanter ' gravel 

 of Arnot Hill. 



IV. — jS^ote on the Soukce or the Pebbles of the Bunter Pebble- 

 beds OF the English Midlands. 



By C. A. Matley, D.Sc, F.G.S. 



rilHE subject of the derivation of the materials which form the 

 J_ Bunter Pebble-beds has given rise to wide differences of opinion 

 and to a voluminous literature. These it is not my intention to 

 recapitulate, as an excellent summary of the subject will be found in 

 Mr. 0. H. Shrubsole's paper of 1903.^ Mr. Shrubsole then gathered 

 together the known evidence, added some new facts of his own, and 

 came to the conclusion that the Midland Bunter pebbles were brought 

 from a southerly direction. This opinion may be said to have held 

 the field until recently, when the question was again taken up by 

 Mr. Jukes-Browne in the third edition of 17ie Buildi>ig of the British 

 Isles (1911). After reviewing the whole evidence and taking into 

 consideration the results of an investigation by Mr. E. C. Martin, 

 which tended to show that the direction of transportation in 

 Somersetsliire in Bunter times was towards the south, Mr. Jukes- 

 Browne abandoned the view he had taken in the second edition (1892) 

 of that work, and now, adopting in the main tlie conclusions of 

 Professor Bonney, considers that the bulk of the pebbles of the 



^ " On the Probable Source of some of the Pebbles of the Triassic Pebble-beds 

 of South Devon and of the Midland Counties " : Q.J.G.S., vol. lix, pp. 311-31, 

 1903. 



