182 A'tmiver-sary Address. 



the tide is ebbing, and the water left in a bank of shingle just 

 above the slope, is finding its way out, by percolating through 

 the sand. Here we have an accumulation above, of water 

 sufficient to work an effect which mere rain from heaven could 

 not accomplish. 



I hope hereafter to have opportunities of putting the ques- 

 tion to abler investigators than myself, whether an accumu- 

 lation was not necessary on the lands above, before water, 

 flowing down the slope, could produce such effects as we wit- 

 ness in the furrowing of various hill sides. But the confor- 

 mation of the moorlands precludes all idea of a lake. 



To the best of my judgment we are irresistibly led to the 

 hypothesis of deep snow-fields, on the tablelands and heights 

 immediately over the localities where the appearances are 

 found ; and of heavy snow-drifts, in places, which continued 

 to discharge water copiously through long periods in summer ; 

 and all this pointing, probably, to a subarctic climate. The 

 theory of morains is by no means applicable here. Provision- 

 ally, I would venture to call these excavations Thaw-furrows. 

 Commencing gradually and upon a minute scale at first, all 

 the features rapidly enlarge as they descend to a certain point, 

 when they again diminish, either in magnitude or in regu- 

 larity, or both; until they disappear on the lower skirts of the 

 hill, or at its bottom. 



From the aspect of the northerly slope of Simonside Hill, 

 above Tosson, as seen from Snitter and Thropton, I believe 

 there must be a very remarkable example of Thaw-furrows 

 there. I have, indeed, for five or six years past, been in the 

 habit of pointing out these striking appearances, nearer home, 

 to my friends, and of trying to understand them. Nay, often 

 have I spoken of reading some notices upon them before our 

 club. 



So long ago as the year 1830, certain deep parallel channels 

 in the subsoil, in the upper part of Ravensworth Wood, struck 

 me, covered as they were by trees, as being very singular and 

 worthy of examination. They are on lofty ground, on the 

 northern declivity of the fell near Pennyfine, with its extensive 

 table-land, probably 700 feet above the sea. The plough and 



