Yorkshire Xaturalists at Hebd^'ii Bridge. 



199 



and by the cells of the leaf being- punctate, as if pricked with 

 the point of a needle. The distribution of this rare hepatic, as 

 far as I know in England is (in addition to Hebden Valley), 

 Deepdale, and Greta Dale, Bowes, where I found it during- the 

 meeting- of the Y. N.U. last year, but did not determine it in time 

 for the report of that excursion. ( I found a very distinct variety 

 of this plant, var. nndulifolia, in a wet sandy ditch by the road- 

 side from Wearhead to Lang^don Beck in Durham.) Jungerniania 

 gracilis forms larg-e tufts on the dry rocks on the moors by the 

 roadside, and J. sp/icerocarpa occurs by the river-side. In damp 

 sandy holes occurs the beautiful Kantia arguta, and on the steep 

 crag's by the river-side are larg^e, flat, brown tufts of Saccogyma 

 viticulosa. 



Mosses. — The rarest moss found is JVeisia crispafa, in fruit, 

 on steep crags by the river-side. This moss, which might be 

 confused with JVeisia tortilis in the barren state on account of 

 its broad nerve, also occurs in Jackdaw Crag- Quarry, Tadcaster, 

 on the limestone cliffs at Gilmanscar, Bowes, and by Welhope 

 Burn, in Durham. Plagiotlieciuin Borreriamim var. colliimm 

 occurs on the vertical face of a larg-e stone. Blindia acuta, in 

 fruit, occurs both in Hebden Valley, and at Lumb Falls, in 

 Crimsworth Dean. By the same falls and in the spray of the 

 water is a very fine and g;lossy, golden-yellow form of var. majus 

 of Plagiothecium denticiilattun. 



Fungi. — Mr. C. Crossland, F.L.S., reports: — The ground 

 having- been so well investigated during the last decade and 

 a half, the mycologists did not, at this early period of the year, 

 expect to add to the list of species. Two were, however, met 

 with in the Hebden Valley, which are new to the parish, viz. : — 

 Polyporus brumalis and Cyphella muscigena, the latter rather 

 a rare species anywhere. Many old acquaintances were seen. 



Geology. — Mr. E. Hawkesworth writes : — ^The most striking 

 geological feature of the district was the examples it furnished 

 of the cutting power of streams, especially when aided by the 

 nature of the rocks cut through. A stream, even small, of 

 fairly high gradient, and alternating beds of shale and harder 

 rocks (in this case grits) present a set of conditions difficult to 

 improve upon for the eventual formation of a deep picturesque 

 valley. The stream, particularly when in flood and running 

 through the shale, easily corrodes it, thus undermining the 

 harder rocks above it, and great blocks of these will sooner or 

 later, through lack of support, break off", and fall down. Nor is 

 this the only action that would take place with such a rock 



1904 July I. 



