THE BRYOLOGY OF LADHILL GILL. 133 



lOs. 6d., is worthy of notice for insects, as well as other branches of 

 Natural History. A watch-maker's eye- glass at Is., which leaves the operator's 

 hands at liberty, is very useful in setting and examining insects; and of 

 pocket lenses, there is the single lens at Is. 6d., and the very excellent 

 lens of three glasses at 3s. 6d. 



January, 1856. • 



NOTES ON THE 

 BRYOLOGY OF LADHILL GILL, (NORTH YORKSHIRE.) 



BY J. H. DAVIES, ESQ. 



Op the dales opening out towards the south, that intersect the moor- 

 lands of north-east Yorkshire, beginning at the west and proceeding towards 

 the sea, Ladhill Gill is the second that presents itself to our attention. 

 Compared with some of the others, its length, which is only about six 

 miles from the source of the stream on the wide expanse of the moor- 

 lands about midway between Snailesworth and Bilsdale, to its junction with 

 the Rye at Hawnby, is quite inconsiderable. At its commencement the 

 beds over which it runs belong to the liassic series, but from the south- 

 eastward dip of strata we gradually pass over earlier deposits as we follow 

 the course of the stream. At first it flows silently along, undermining 

 its way over the heathy surfaces of the moorland, diversified by beds of 

 Sphagnum and Polytrichum commune. After pursuing a tortuous course for 

 some distance, the valley sinks deeper, and the stream rushes over its rocky 

 channel between sloping banks, clothed with hazels and alders; now whirling 

 in eddies amongst the confused rocks, and forcing its way between them, anon 

 dashing down some steep declivity, and now rippling along a smooth surface 

 of solid rock. Sometimes the sides of the glen are precipitous, and covered 

 with trees, principally young oak, ash, alder, and hazel; sometimes you catch 

 a glimpse of the moor, and sometimes it is quite exposed, and you are tempted 

 to leave the stream for a time to hunt amongst the rocks and '^stone walls 

 grey with mosses," to find, in all probability, Hedwigia ciliata and Weissia 

 cirrhata. Returning to the stream, Tetrodontium Brownianum may be seen 

 on the shady rocks, which in some places overhang it, and on the trees 

 Orthotrichum Bruchii, Isothecium myurum, etc. In the stream itself you 

 may collect Racomitrium aciculare, Dicranum Jlavescens, Schistidium apo- 

 carpum, (and its variety rivulare,) Hypnum plumosum, and a host of 

 others. In several places the liassic shale is entirely exposed, and the 

 water constantly dripping down the surface, prepares excellent situations foi* 

 such species as Dicranum squarrosum, Hookeria lucens, Bartramia fontana 

 and calcarea, Mnium punctatum,, Fissidens adiantoides, Bryum pallens and 

 Wuhlenbergii, etc. 



