INTRODUCTORY REMARKS. 5 



as the dark engraving of the maps would, in many cases, 

 have rendered the colours, if no deeper than those recom- 

 mended in that paper, hardly visible.* The sections have 

 been formed on the same system of colouring, and when 

 other colours were required, those were selected which ap- 

 peared to harmonize best. In regard to the objects of these 

 sections it may be stated, that they were selected from 

 all those points where the connections of the rocks are 

 in any way interesting. The specimens which accom- 

 pany the memoir, were selected in the same manner : no 

 rock which the author considered interesting did he in- 

 tentionally pass. In regard to the paucity of the speci- 

 mens which have been collected in Linlithgowshire, it may 

 be remarked, that few rocks were found which had not been 

 already noticed in the counties of Haddington and PMin- 

 burgh, and, as specimens of these had been selected, the 

 fact of finding the same rocks in a different locality, ap- 

 peared to render their collection unnecessary. 



There still remains to be noticed one circumstance attend- 

 ing this essay, and which may perhaps require explanation ; 

 and this is the fact of there being in it no attempt to give 

 details connected with the " Coal Workings.' 1 '' The reason 

 which the author had for not entering on this part of the 

 subject was, that he considered that such an investigation lay 

 more in the way of the professional coal- viewer, than of one 

 engaged in purely geological investigations. He did not, 

 therefore, attempt to draw up sections or ground-plans of 

 coal- workings, or to inquire into the quantities of known coal. 



* The maps here referred to are those which were lodged with the es- 

 say. They were those published by Mr Thomson of Edinburgh. 



