285 

 THE MOSSES & HEPATICS OF DENBIGHSHIRE. 



D. A. JONES. 



The part of the county of Denbigh which lies to the south- 

 east of the Berwyn Mountains and Cyrn y brain forms a well- 

 defined rectangular area about twenty-seven miles long and 

 ten miles broad. It is divided into two nearly equal sections 

 by the River Dee — one to the north-east and the other to the 

 south-west of the river. 



These notes deal mostly with the distribution of Mosses and 

 Hepatics in the former portion, to which are added a few records 

 for Llandegla and Glynceiriog, north and south of the area 

 respectively. 



The district consists of hills and dales. The land rises 

 gradually towards the north-west. Above Llangollen it 

 reaches an elevation of 1,648 feet in the fine Eglwyseg Rocks 

 which are continued in a northerly direction as far as World's 

 End. The latter contains some of the most prolific rocks in 

 cryptogams in the county. To the north-east of this part 

 the land attains its highest point at Cyrn y brain, 1,839 ^ eet - 

 Again, the hills that lie to the north-west of Wrexham have 

 an altitude of over 1,000 feet at Bwlcbgwyn increasing to 1,500 

 feet on Minera Mountain. Beyond this high ground a wide 

 stretch of moorland covered with heather extends as far as 

 World's End to the south-west. 



The vales of Llangollen and Gresford, watered by the 

 Rivers Dee and Alun respectively, occupy opposite ends of 

 the district. 



Nant y Ffrith is a deep ravine running from Ffrith to 

 Bwlchgwyn. Its caves and miniature waterfalls are very 

 beautiful. The outcrops of Millstone Grit and limestone 

 produce a varied and interesting moss and hepatic flora. 

 Some of the rocks forming the right side of the basin of one of 

 the larger waterfalls are lined with extensive cushions of 

 Weisia curvirostris var. commutata, covered with hundreds of 

 capsules. The higher rocks lower down the river and on the 

 same side form a substratum on which great masses of 

 Metzgeria pubescens grow, a plant not elsewhere recorded for 

 the Principality. The Sandstone caves — floors and sides — are 

 literally covered with cryptogams — Brachythecium velutinum 

 in close green and silky sheets, Web era proligera,.W. albicans, 

 together with Plagiochila .asplenioides var. humilis, Cepha- 

 loziella stellulifera, Calypogeia arguta and other minute hepatics. 

 The stream that flows through the ravine forms the boundary 

 between the counties of Denbigh and Flint. 



Geologically, the district shows the three principal divisions 

 of the Carboniferous Formation. They are : — 



1917 Sept. 1. 



