ON THE ERRATIC BLOCKS OF ENGLAND, WALES, AND IRELAND. 101 



Sixteenth Report of the Committee, consisting of Professors J. 

 Pkestwich, W. Boyd Dawkins, T. McK. Hughes, and T. Gr. 

 BoNNEY, Dr. H. W. Crosskey, and Messrs. C. E. De Range, H. 

 Gr. FoRDHAM, D. MACKINTOSH, W. Pengelly, J. Plant, and 

 K. H. TiDDEMAN, appointed for the puoyose of recording the 

 position, height above the sea, lithological characters, size, and 

 origin of the Erratic Blocks of England, Wales, and Ireland, 

 reporting other matters of interest connected xvith the same, 

 and taking measures for their preservation. {Drawn up by 

 Dr. Crosskey, Secretary.) 



It was expected that this Committee -would be able at an early date 

 to summarise and conclude its reports ; but as its existence and object 

 are becoming more generally known, so large a number of new observa- 

 tions are being forwarded, that it is necessary that its work should still 

 be carried on. 



Among the important points that are being brought to light are : (1) 

 the very distinct grouping of erratics in various localities, showing clearly 

 that they have travelled in definitely marked courses ; (2) the determi- 

 nation of the character of these groups by the physical geography of the 

 country — ridges of existing highlands and hills effectually stopping or 

 diverting the courses of the streams of boulders ; (3) the occasional 

 crossing of the groups of boulders — the meeting places of different 

 streams being determinable ; (4) the deposition of erratics at different 

 periods. 



When the summary of the reports is prepared, these facts will be 

 found to stand out with great clearness and their bearing upon the glacial 

 theories will prove to be of large importance. 



YOKKSHIRE. 



Very remarkable facts were recorded in last year's report, respecting 

 the boulders in the parish of Ingleby Greenhow, Northallerton ; where 

 blocks from the Lake district, from the S.W. of Scotland, from the 

 Cheviot hills and adjoining districts, from more distant northern parts 

 of Scotland, are intermixed with glaciated blocks of local origin. 



The Rev. John Hawell supplements the information previously given 

 and has examined 3G5 boulders (Professor Bonney and Mr. C. T. Clough 

 giving their kind assistance in the determination of some of the specimens) 

 with the following results : — 



(1) Shan granite .......... 3 . 



(2) Granite of Criffel type 1 



(3) Dolerites 9 



(4) Sj'enite or diorite (Scotch) 1 



(5) Quartzite .......... 1 



(6) Quartzose rock ......... 1 



(7) Quartzose gieywacke 1 



(8) Vein quartz 1 



(9) Quartz-felsite (from St. John's Vale?) 2 



(10) Felsite 1 



<11) Porphyrites from Cheviots 67 



(12) Porphyrites from Cheviots or S. Scotland ... 7 



