358 PEOCEEIOTGS OF THE GEOLOGICAL SOCIETY. [Feb. 26, 



from the volcanic districts of Wales ; and I believe that a study of 

 the configuration of the ground would render it probable that they 

 came from the Berwyn hills, and not from Cader Idris, the Arans, the 

 upper Conway district, or the Snowdon range. Angular felspathic 

 blocks may be found scattered on Halkin mountain, Flintshire. These 

 may have come from Snowdon. 



I have not noticed striae on any of the large felstone boulders 

 above mentioned ; but the extent to which their surface is weathered 

 would have effaced any previous marks of giaciation. 



In the large boulders or groups of large boulders mentioned in this 

 paper I have not noticed any agreement as to the position of the 

 glaciated surface, or tbe direction of the striae or longitudinal axes. 



In concluding this article I would redirect attention to the groups 

 of large boulders betAveen Wolverhampton and Bridgenortk, long ago 

 discovered by Sir Roderick I. Murchison, and elsewhere described 

 by myself*. I believe they include both Eskdale and Criffell 

 granite — the former having travelled about 130 miles, and the latter 

 170 miles ! The Swiss Geological Commission make a wonder of 

 boulders having been transported from the Alps to distances of 120 

 and 150 milesf . But in England, I believe, we have not only greater 

 wonders connected with the transporting-power of ice, but (taking 

 the East-Anglian and north-west-of-England drifts together) a 

 more varied and complete series of glacial and postglacial deposits 

 than is perhaps to be found in any other part of the world. 



Postcript. 



'Reexamination of the Trescott Boulders. — A few days ago, I took 

 a journey to Wolverhampton with the view of being able to speak 

 more positively concerning these very far-travelled stones ; for when 

 I saw them four and a half years ago, I had not traced the granites 

 found in the drifts of the N. W. of England back to their sources. 

 In the fine rounded gravel west of Wolverhampton (the horizon of 

 which relatively to the drifts further north is still uncertain), I saw 

 many pebbles of Eskdale, but scarcely any of Criffell granite. I was 

 therefore surprised to find that all the large blocks (as well as smaller 

 fragments) of granite around Trescott were Criffell, with the excep- 

 tion of two blocks, which resembled the granite now quarried near 

 Creetown, Kirkcudbrightshire. I saw several hundreds of them, and 

 hammered a great number. Some of the blocks contained a few large 

 crystals of felspar, generally white, but sometimes of a brownish 

 hue — in this respect resembling granite now quarried by the Shap 

 Company near Dalbeattie. In the parishes of Trescott and Trysull 

 they are quite as thickly strewn as on the plain of Cumberland 

 opposite Criffell mountain^, and actually present a much greater 



* Scenery of England and Wales. 



f Scheme for the Conservation of Boulders, Proc. Koyal Soc. Edin. 1870-71. 



I The Criffell boulders on the plain of Cumberland are generally more or less 

 rounded, and appear to be associated with the Lower brown clay. I believe they 

 were transported by coast-ice while the sea was comparatively shallow. I have 

 nowhere seen them at a greater height on the hill-sides than 400 feet above the 

 present sea-level. 



