156 T. Mettard Meade — Physiography of the Lower Trias. 



rivers draining the mountainous region to the north." As I have 

 not done so in my original paper, 1 will now deal specifically with 

 this notion. 



The first difficulty in accepting it arises from the generally sparse 

 distribution of the pebbles throughout the Bunter Sandstones of 

 Lancashire and Cheshire, combined with the much greater develop- 

 ment of conglomerate beds further South and in the Midland 

 Counties. It is true that there are certain horizons in the Bunter 

 of Lancashire and North Cheshire containing pebbles which have 

 been dignified with the term " conglomerates " to distinguish them 

 from the more prevalent homogeneous sandstones ; but of genuine 

 conglomerate, such, for instance, as may be seen at Market Drayton 

 and Bridgnorth, there is a great absence. 



Indeed, so much so is this the case that I am about to exhibit at 

 the Liverpool Geological Society a block of conglomerate taken from 

 a bed only nine inches thick disclosed by sewer excavations in 

 Church Road, Walton. 



If the pebbles were generally derived from the north by river 

 transport, we should expect to find the conglomerate beds increasing 

 in thickness and the pebbles in size in that direction. The contrary 

 is the case. 



Then as to the sand : — an inspection of the geological map of 

 Scotland shows such a diversity of rock-structure, and there exist 

 such lithological differences in the various areas that would have 

 drained into these two hypothetical rivers, as to seem irreconcilable 

 with the required travel of sand only, southwards. 



To speak fairly, this is a difficulty that affects more or less any 

 hypothesis, but it is doubly intensified on the subaerial and river 

 theory of the origin of the Bunter Sandstones. 



It will be seen that Prof. Bonney misconceives the facts in speak- 

 ing of the Bunter generally as a " conglomerate." It is in Lancashire 

 and Cheshire essentially a sandstone, and many of the so-called 

 " pebble beds " do not possess a single pebble ! Prof. Bonney 

 writes from a locality where he is under the influence of " a practi- 

 cally unbroken pebble-bed at least thirty yards thick " ; but this is 

 in Staffordshire, and I claim the fact as being more in unison with 

 my view of the marine origin of the Bunter than with its possible 

 derivation from the north by river action. Such a conglomerate 

 bed does not to my knowledge exist in the Trias anywhere between 

 here and Scotland. 



I do not know whether Prof. Bonney has read the two papers 

 referred to on " Tidal Action." If not, he may possibly on perusal 

 alter his views as to the efficiency of tides to move such pebbles as 

 are found in the so-called " Pebble Beds." 



There is, I know, great misconception prevailing on the subject of 

 tidal action. The writers of geological text books, judging from 

 all that I have read, and I have examined many, are mostly " quite 

 at sea " on the tides, and seek to confine their effects to the shore ! 

 Prof. Bonney asks, " Is there any evidence that these currents would 

 be capable of sweeping about pebbles 3 or 4 inches in diameter ? " 



