560 THiRSK NATURAL HISTORY SOCIETY. [^September, 



the magnesian limestone at Wetherby is reached ; so that we 

 have two distinct portions of Wharfdale : the upper or limestone 

 part, with narrow green meadows, and a clear free stream over- 

 hung by mural precipices with innumerable undulations and 

 sinuosities ; the lower or gritstone part broader and more sylvan, 

 approached on each side down a gradual slope of heathery moor- 

 land. The Leeds Northern Railway passes through the southern 

 flank of the dale by a long tunnel at Brarahope. 



" On the 4th of j\Iay I left the line at Arthington station to 

 walk ten miles up the dale to Ilkley. By the streamside near the 

 Pool paper-mills is Lamium Galeobdolon. By the Wharfeside, 

 above Otley, about the place where a little beck from the south 

 joins the main stream, is a good deal of Salix undulata in a 

 plainly indigenous condition, of which more hereafter. The other 

 Willows which I noticed in the dale are, fragilis, alba, purpurea, 

 rubra, viminalis, Smithiana, cinerea, Caprea, and fusca. Coch- 

 learia officinalis grows here by the riverside, and to my know- 

 ledge all along from Bolton Woods downwards to Thorp Arch. 

 The ' Cybele ' restricts the name officinalis " entirely to the shore 

 plants and to those merely naturalized inland through cultiva- 

 tion," and speaks of C. alpina as belonging to the Highland type 

 of distribution ; but with us in Yorkshire, besides growing on the 

 coast and on the hilltops, the Scurvy-Grass (plainly one species 

 only) is one of the frequent indigenous plants of the western 

 dales, and is also sometimes carried down by the streams into the 

 central valley, like Myrrhis odorata or Rumex aquaticus. The 

 Myrrhis is here also ; and at this part of the Wharfe, which is 

 220 feet above the sea level, I first noticed Stellaria nemorum, 

 which is continued as far up the stream as Bolton Woods. Over 

 Otley the southern flank of the dale becomes grit-crested and 

 heather-clad, and attains an elevation of 920 feet, so that there 

 is a slope of 700 feet from the hilltop to the streamside. Soon 

 after this, on the same side, Rumball's Moor stands out into the 

 dale and narrows it considerably. The hydropathic establish- 

 ment called Ben Rliydding stands on the slope of this moor, at 

 an elevation of perhaps 700 feet. In the valley down beloAV it, 

 is one of Dr. Carrington^s stations for the smaller Orthotricheae. 

 The hedges that margin the roads hereabouts yield 0. pallens, 

 tenellum, and stramineum ; they grow mostly in small tufts, 

 upon old branches of Hazel and Hawthorn. By the\treamside 



