THE YORKSHIRE BOULDER COMMITTEE 

 AND ITS SIXTEENTH YEAR'S WORK, 1901-1902. 



PERCY F. KENDALL. F.G.S., Leeds, Chairman. 



AMI 



J. H. HOWARTH, F.G.S.. Halifax, Hon. Secretaiy. 



The results of the work carried on during- the year with un- 

 diminished eners^y all over the county are of exceptional 

 interest. 



Records which call for particular notice are the boulder of 

 diabase at Aldfield, near Ripon (the most westerly point to 

 which rocks foreign to the district have been traced) and the 

 boulders of limestone at Escrick, which resemble some of the 

 rocks of Swaledale. Carboniferous limestones rarely displav 

 characters by which their exact place of origin can be deter- 

 mined. 



A visit paid by the Yorkshire Geologfical and Polytechnic 

 Society to the Tweed Valley two years ag^o enabled members 

 of the Yorkshire Boulder Committee to acquire a familiarity 

 with some oi the distinctive rocks of that region, with the result 

 that the Hag^gis rock, so well known to Scottish geologists, 

 is reported from several localities in the East of Yorkshire. 



The Interest of these observations is, however, eclipsed hv 

 a remarkable series of boulders noted by Mr. H. B. Muff, now 

 of the Geological Survey of Scotland. Mr. Muff submitted to 

 his colleagues, Messrs. B. N. Peach and E. H. Cunningham- 

 Cralg-, a series of specimens of boulders from the country round 

 Whitby, collected by Messrs. Muff and Sheppard, and among" 

 them were recognised rocks from the Southern Uplands of 

 Scotland, such as Haggis rock, Queensbury grits, and radlo- 

 larian chert; Old Red Sandstone conglomerate of a Scottish type 

 and various volcanic rocks of which the source may be in either 

 the Cheviots, Pentlands, or Ochills. The authorities quoted 

 consider that It Is unsafe to assign porphyrites specifically to the 

 Cheviots, as rocks of the same petrological character occur as 

 far north as the Ochills. The succeeding determinations show- 

 that there Is no Improbability In this suggestion, for they include 

 a large suite of quite distinctive Highland rocks, namely, Leny 

 grits. Highland schists of Perthshire, Moine schists, and Ben 

 Ledi grits. 



Additional localities in Yorkshire are given for the Scandi- 

 navian rhomb porphyries, augite- and zircon-syenites, and the 



Naturalist. 



