TRANSACTIONS OF THE SECTIONS. 97 



been met with at one locality in the latter county, where Cephalaspis occurs. 

 The most characteristic feature of the formation is the enormous development of 

 its interbedded volcanic rocks. Between Edinburgh and Lanariishire, also, there 

 occurs in this formation a local but violent imconformability, connected probably 

 with some phase of the contemporaneous volcanic activity of the region. 



Most of the detailed work of the Sm-vey has lain upon Carboniferous rocks. In 

 the lowest formations of this system, known as the Calciferous Sandstones, the 

 Survey has now been able to trace a twofold division completely across the coun- 

 try, from sea to sea, viz. a lower group of red sandstones, and a higher group of 

 white sandstones, gi-een, grey, and dark shales, cement-stones, limestones, and occa- 

 sional coal-seams. All these strata lie beneath the true Carboniferous Limestone. 

 Thej'' are becoming daily more important from their containing in some places 

 highly bituminous shales, from which paraffin oil can be made. The Carboniferous 

 Limestone series, with its valuable coals and ironstones, has been mapped, and in 

 great part published, for the eastern and south-western coal-fields ; and this is also 

 the case with the Coal-measures. Much additional information has been obtained 

 regarding the development of volcanic action in central Scotland during the Car- 

 boniferous period. 



The Permian basins of Ayrshire and Thornhill have been surveyed and in great 

 part published. Much fresh light has in the course of this Survey been thrown on 

 the interesting Permian volcanoes of the south-west of Scotland. 



Attention has been continuously given to the superficial accumulations. These 

 are now mapped in as great detail as the rocks underneath, and plans are being 

 prepared with the view to an issue of maps of the surface geology. 



Bj^ a recent order of the Director-General, each one-inch map is now accompa- 

 nied at the time of its publication, or as soon thereafter as possible, with an expla- 

 natory pamphlet, in which the fonn of the ground, geological formations, fossils, 

 rocks, faults, and economic minerals are brieny described, and such further infor- 

 mation given as seems necessary for the proper elucidation of the map. These 

 pamphlets are sold at a uniform price of hd. Detailed vertical sections are pub- 

 lished for each coal-field. For the construction of these sections, records of 

 boring operations are procured and recorded in the register-books of the Survey. 

 Since 1867 more than 312,200 feet of such borings have in this way been entered 

 in cm" books. Sheets of horizontal sections on a large scale are likewise issued to 

 form, with the maps and explanations, a compendium of the geological structure 

 of each large district. 



Another feature of the work of the Survey is the collection of specimens of the 

 rocks and fossils of each tract of country as it is surveyed. Since my previous 

 Report to this Section of the British Association, we have collected 1011 speci- 

 mens of rocks, and 7500 fossils. These are named and exhibited, as far as the 

 present accommodation will permit, in the Museum of Science and Art at Edin- 

 burgh. 



The work of the Geological Survey is can-ied on, as I have said, under the guid- 

 ance of its Director-General, Sir Roderick Murchison, a name which has long been 

 a household word at the meetings of the British Association, and one to which I 

 am sure you will permit me to make on this occasion more than a passing reference. 

 While the Survey advances, as I have shown, steadily over the face of the country, 

 imravelling piece by piece the complicated details of its geological structure, to 

 Sir Roderick belongs the rare merit of having himself led the way, by sketching 

 for us, boldly and clearly, the relations of the older rocks over more tlian half of 

 the kingdom. Much must undoubtedly remain for future investigation, but his out- 

 line of the grand essential features of Highland geology will ever remain as a monu- 

 ment of his powers of close yet rapid observation aud sagacious inference. At one 

 time I had hoped that the Chair of this Section might be filled by him, and that 

 we should be permitted to listen anew to his expositions of the rocks of his native 

 countrj'. There is no one among us who does not regret the absence of the fami- 

 liar face and voice of the veteran of Siluria. AVe meet once more on Scottish 

 ground, aud for the first time we have not here with us the man who has laid a 

 deeper, broader impress on Scottish geology than any other geologist either of past 

 generations or of this. There is, however, on the present occasion, a special cause 



1871. 7 



