ON ERRATIC BLOCKS OF THE BRITISH ISLES. 553 



The Committee is also enabled to announce tlie recognition amongst 

 the far-carried erratics of the East Coast of England of a considerable 

 number of Norwegian rocks from localities which were not previously 

 known to have yielded boulders to the English drift. 



The Secretary spent a month during the summer of 1897 in Norway, 

 between Christiania and Christiansand, collecting rocks for comparison with 

 the erratics of the East Coast of England. He brought away a large quantity 

 of material illustrating important petrological types, and has now dis- 

 tributed about 300 specimens amongst English workers in glacial geology, 

 to whom they may be useful. Other sets will be lodged in public museums. 

 A series of East Coast erratics, collected by Mr. J. W. Stather, F.G.S., 

 and Mr. Thomas Sheppard, was taken to Christiania and submitted to 

 Professor Broggei', who had kindly consented to examine them. Professor 

 Bi'ogger's examination was not carried to completion, as the thin sections 

 which should have accompanied the specimens had gone astray in the 

 post, but some rocks were nevertheless singled out by him which possessed 

 such marked characteristics as to permit of positive identification. These 

 determinations are of so much interest and importance that it has been 

 thought desirable to publish them in this report rather than to wait for a 

 more complete statement. 



The well-known Rhomb Forplujries yielded examples from the Ringe- 

 rike, Tonsberg, and Tuft (in the Langendal districts). 



Laurvikite (Augite-Syenite) of the type which prevails over such large 

 areas southward of the latitude of Christiania was recognised. These are 

 rocks with which English geologists have for some time been familiar ; 

 but, besides these, Professor Brogger found the Pyroxenite of Fettnedt, 

 Christianiafjord ; a basic rock from Hitterdal (this is a very pronounced 

 type, regarding which Professor Brogger spoke with great confidence) ; 

 the Labradorite porphyrite of Mos (on the east side of the Skager Rock 

 south of Drobak) ; and rocks from the neighbourhood of Drammen. In 

 addition to these, there are examples of a Labradorite forpliyrite with 

 porphyritic conspicuously zoned felspars, which is known as an erratic in 

 Norway, but has not been traced in situ. 



Finally, Professor Brogger recognised three examples of sandstone or 

 grit representing the curious Sjyaragmit conglomerate which covers a vast 

 area in the high mountainous interior of Scandinavia northward of Christi- 

 ania. The specimens in question may have come from Gudbrandsdal, about 

 the northern part of Lake Mjesen. 



A coarse granite collected by Mr. Sheppard, Professor Brogger con- 

 sidered to resemble the rocks of Ragunda in Angermanland, a conclusion 

 confii-matory of Dr. Munthe's recognition of a boulder composed of a 

 similar rock (see 1897 Report, p. 351), and which occurs also, according to 

 Mr. Crofts, at Easington (see p. 554). 



YOKKSIIIRE.I 



Communicated by the Yorkshire Boulder Committee. 

 Secretary, Mr. J. H. Howarth, F.G.S. 



Reported by Mr. "VY. Gkegson, F.G.S. 



Mount Grace Priory, 7 miles E. of Northallerton — 

 1 Shap granite. 



' This report will be published in extcnso in the Katuralist. 



