ON ERRATIC BLOCKS OF THE BRITISH ISLES. 231 



Erratic Blocks of the British Isles. — Mghth Report of the Gorrmiittee 

 consisting of Dr. J. E. Marr (Chairman), Mr. P. F. Kendall 

 (Secretary), Professor T. G. Bonney, Mr. 0. E. De Hance, 

 Professor W. J. Sollas, Mr. E. H. Tiddeman, Rev. S. N. 

 Harrison, Dr. J. Horne, Mr. F. M. Burton, Mr. J. Lomas, Mr. 

 A. R. DwERRYHOUSE, Mr. J. W. Stather, Mr. W. T. Tucker, 

 and Mr. F. W. Harmer, appointed to investigate the Erratic Blochs 

 of the British Isles and to take measures for their preservation. 

 (Braivn up by the Secretary.) 



The majority of the records received during the present year has been 

 contributed by workers in Yorkshire, and it is satisfactory to note that 

 one of the few areas in that county inadequately studied hitherto is now 

 receiving attention. The Thirsk Naturalists' Club has organised a sub- 

 committee acting in co-operation with the ^Yorkshire Boulder Committee, 

 and the first results of its investigations in the Vale of Mowbray are 

 now presented. The present writer visited Thirsk in the spring of this 

 year and identified many boulders which will serve as types for the 

 guidance of the local workers. The observations made in the Vale of 

 Mowbray may be said to close up the last gap in the network of obser- 

 vations which now extends over the whole of the great county of York 

 from the Tees on the north to Sheffield on the south, and from Ingleton on 

 the west to the sea. The thoroughness with which the search for erratics 

 has been made is very gratifying, yet the fact that fresh types of erratics 

 still continue to be recorded shows that this well-worked field is far from 

 being exhausted. 



In the present report we record the recognition by Professor Brogger 

 of yet another type of igneous rock derived from the prolific country near 

 Christiania, and the visit of the Yorkshire geologists to the Tweed Valley, 

 referred to in the report presented last year, has borne fruit in the 

 identification at two localities in Yorkshire of examples of the trachytes 

 so characteristic of the south-east of Scotland. Other boulders worthy of 

 mention are the small boulder of Borrowdale Ash, found by Mr. Gregory, 

 near Keighley, at an altitude of 900 feet O.D. This is an interesting 

 confirmation of a record to be found in the report for the year 1875. 

 Mr. Hemingway sends some valuable notes on the puzzling drift-area 

 about Barnsley. 



A welcome contribution to the knowledge of a little known area is 

 the report on boulders in co. Durham sent by the Rev. W. J. Wingate. 



A series of records from East Anglia (including the first sent to this 

 Committee from the county of Norfolk) shows that valuable results would 

 repay workers in the district ; and it should be pointed out that with the 

 centralisation of the brickmaking industry at a few centres, and the 

 general introduction of road-metal from distant places, the opportunities 

 for observation are being rapidly diminished by the closure of brickyards 

 and gravel-pits which furnish at present the most numerous and con- 

 venient opportunities for the study of erratics, especially the smaller 

 ones, at the same time the larger boulders are being broken up for 

 road-mending. It should here be again pointed out that the smaller 

 stones are frequently of greater interest than large ones. Some of the 



