ANNIVERSARY ADDRESS OF THE PRESIDENT. 1x1 



Regions in which the Systems exist. 



Systems 



Orientations reduced 

 to Bingerloch 



E. 4 32 N. 



E. 22 18 N. 



N. 28 19 E. 



E. 15 6N. 



N. 15 46 W. 



Isle of Wight, Tatra (a mountaiu 

 S. of the Carpathians), Greece, 

 Eastern Alps, Jura. 



Greece, France. 



Italy, Sicily, Northern Africa, 

 Hungary, Poland, Crimea, Asia 

 Minor, the Hartz, Cantal and 

 Mont Dore, Norway, Sweden. 



S.E. of England, N. of France, 

 S.W. of France, Spain, Shores 

 of the Mediterranean, N. of 

 Africa, Atlas, Caucasus. 



Greece, Italy, Sicily. 



XVI. Isle of Wight and 

 Tatra. 



Calcaire d'eau douce 

 superieur(Paris basin). 



XVII. ErjTnauthus and 

 Sancerrois. 



Faluns dela Touraine. 

 Molasse (containing 

 shells). 



XVIII. Western Alps.... 

 Terrain de transport 



ancien. 



XIX. Principal chain of 

 the Alps (from Le Vallais 

 to Austria). 



Diluvium. 



XX. Tenare, Etna, and 

 Vesuvius. 



I now proceed to a general review of the geological structure of 

 the Palaeozoic rocks of Wales and of the adjoining English counties. 

 I begin with N. Wales. 



The three leading keys to the general structure of this district are 

 the three anticlinal lines of Caernarvonshire, Merionethshire, and 

 the Berwj^ns with their synclinals. That of Caernarvonshire lies im- 

 mediately on the west of the great Caernarvon range of Snowdon, 

 Moel Hebog, &c., running in a direction N.N.E. and S.S.W. To- 

 wards the north it is interrupted by great transverse faults on the 

 north of Snowdon, and on the south, as it approaches the coast of 

 Cardigan Bay, it is interfered with by derangements of the strata 

 about Tremadoc. The great Merioneth anticlinal runs from Cader 

 Idris in a direction parallel to the former, but gradually loses its 

 anticlinal character to the northward before it reaches the Shrewsbury 

 and Bangor road, the beds at this extremity dipping in different 

 northerly directions so as to form a kind of apse. The great mass 

 of the Snowdonian mountains occupies the synclinal space between 

 the Caernarvon and the more northern portion of the Merioneth anti- 

 clinal, the crest of the Caernarvon range, however, running nearer to 

 the former than the latter of these lines. The Berwyns anticlinal 

 is a less important feature than the two preceding ones. It ranges 

 just to the west of the principal mass of the Berwyns, running some- 

 what obliquely to the crest of those mountains. On their eastern 

 side the beds again dip towards the N.W. and thus form another 

 synclinal trough in which the mass of the Berwyns is situated, as the 

 Snowdonian mass is situated between the Caernarvon and Merioneth 

 anticlinals. On the south this line soon loses its anticlinal character 

 and terminates to the northward before it reaches the Dee, the beds 

 forming abruptly an apse round this extremity, and passing under 

 the Upper Silurians of Denbighshire. Between the Merioneth and 

 Berwyn anticlinals the dip is for the most part persistent in the 



