REPORT OF MEETINGS FOR 1905 255 



Scottish Eock-specimens, along with the maps and sections 

 which these are meant to explain, are exhibited in wall-cases 

 on the outer side of each Corridor. In the desk-cases along 

 the walls a set of Geological Survey maps are exhibited in 

 direct connection with specimens of the rocks themselves, 

 which are arranged under their respective Counties. The 

 principle followed in the arrangement of the specimens is 

 largely chronological, in the carrying out of which each is 

 numbered, and those rocks reckoned the oldest in the 

 particular district are placed first and marked with the lowest 

 numbers, while those regarded of later age follow in strati- 

 graphical order and are numbered accordingly. To enable 

 the enquirer to find readily the position on the map of any 

 Eock- specimen in the Collection, an elaborate system of 

 division into rectangles has been devised, a reduced copy 

 of which is printed on the labels attached to the specimens, 

 so that a coloured subdivision of the key-diagram forms a 

 guide to the corresponding geological colouring on the maps, 

 and to the geological and geographical positions of any rock 

 of which the visitor may be in quest. The number of Rock- 

 specimens exhibited in the wall-cases exceeds four thousand, 

 and to these have to be added three thousand others, which 

 are exhibited partly along with the maps in the desk-cases, 

 and partly in the spaces beneath. In addition, and in order 

 to convey an accurate idea of the weathered aspect of such 

 rocks, as they would present themselves to any investigator 

 on the spot, an interesting series of examples is displayed on 

 a shelf beneath the maps. In arranging the Collection 

 unnecessary duplication has been avoided by displaying each 

 of the larger petrographical groups most fully under the 

 particular district in which it happens to be typically 

 developed, as, for example, the Silurian Rocks under Ayr- 

 shire, Lanarkshire, Peebleshire ; and the Carboniferous Rocks 

 under Fife and the Lothians. 



The North Hall is almost entirely occupied by a large 



assemblage of the Minerals of Scotland, acquired 

 Scottish partly by gift, and partly by purchase, and 



Mineral including nearly one hundred and eighty species. 



Collection. During the past thirty years contributions by 



various collectors have been made, notably by 



