176 Reviews — Merionetltsliire. 



the Trimingliain Chalk has been shown to be of higher horizon than 

 that found in any other English locality, no one has yet been able to 

 determine its exact relationship to other English Chalk in situ. 

 A boring at Mundesley or at some other point on the eastern coast 

 appears to be necessary if it is desired to make our knowledge of the 

 English Challi complete. It is to be earnestly hoped that some such 

 boring will be undertaken at no very distant date. 



IiEl"VIE!-V^S. 



I. — Cambeidge County Geographies. 

 Merionethshire. By A. Morris, F. R. Hist. Soc. Small 8vo ; 

 pp. 166, with a Physical and a Geological Map, and 48 illustrations 

 in the text; cloth boards. Cambridge University Press, 1913. 

 Is. Qd. each. 



MERIONETHSHIRE is a maritime county of North Wales, open 

 to Cardigan Bay on its western side, and enclosed north, east, 

 and south by the counties of Carnarvon, Denbigh, Montgomery, and 

 Cardigan respectively. It is more mountainous than any other part 

 of North Wales, except perhaps Carnarvonshire. Its deep and 

 secluded valleys, with the ruggedness and variety of its elevated 

 districts, give it a particular charm and interest. The varied 

 panoramic views from its heights surpass anything to be seen in Wales. 



The nature of the rocks enables a portion of the country to be 

 devoted to slate-quarrying. It is the only county in Wales in which 

 gold has been found (at Dolgelly) in quantities sufficient to pay for 

 working. (See Geol. Mag. 1865, p. 558.) 



No isolated, solitary peak of the Welsh mountains shows such 

 a wreck of stone as Cader Idris. With an elevation of 2,927 feet above 

 the sea-level, it marks the starting-point from which a long chain of 

 primitive mountains extends in a north-east direction to the Berwyns 

 and on to the borders of Shropshire, (p. 13.) 



The Harlech Dome, as it is called by geologists, is a large, 

 irregularly-oval track, lying between Dolgelly and Harlech, and 

 ranging northward to Maentwrog. It is occupied by unfossiliferous 

 grits, and purple and green slates. It holds a very important place 

 in the physical features of North Wales, being the site of the great 

 Merionethshire anticlinal, in which the rocks dip in opposite directions 

 like the roof of a house. On the flanks of these sloping rocks the 

 fossiliferous flags and grits of the Lower Cambrian Series are observed 

 to rest. (p. 35.) 



The Lingula Flags are divided into three groups — the Maentwrog, 

 the Festiniog, and the Dolgelly Groups. The first is characterized by 

 its jointed dark-blue ferruginous slates, the second by hard micaceous 

 flags, and the third by soft, black slate, which shows a black streak 

 when scratched, (p. 35.) 



The range between the Rivers Eden and the Mawddach in the 

 neighbourliood of Dolmelynllyn has always been famous for its fossils. 



The Ordovician occupies the largest area in North Wales. It spreads 

 in numerous undulations around the towns of Bala and Corwen ; it 



