ON THE ERRATIC BLOCKS OF ENGLAND, WALES, AND IRELAND. 221 



3. Coarse felsitic ash ; no stria?, no smoothing. Size, 4 ft. 6 in. x 4 ft. 

 X 2 ft. 6 in. 



4. Pale felspathic rock, probably an altered ash or fault rock from 

 Arenig ; no stria?, no smoothing. Size, 3 ft. X 2 ft. x 1 ft. 6 in. 



5. Very coarse streaked volcanic ash, with crystals of felspar ; no 

 stria?, no smoothing. Size, 3 ft. 6 in. x 3 ft. X 2 ft. 



6. Dense felspathic ash with crystals of orthoclase ; no stria?, no 

 smoothing. Size, 3 ft. x 2 ft. X 2 ft. 



7. Altered felspathic ash with crystals of orthoclase ; no stria?, no 

 markings. Size, 2 ft. 6 in. X 2 ft. x 1 ft. 9 in. 



8. Ironstained greenish grit with enclosures of shale. Size, 2 ft. x 

 1 ft. 6 in. x 1 ft. 



9. Rough felspathic rock with enclosures of grey felspar; no stria?, no 

 smoothing. Size, 2 ft. 6 in. x 2 ft. x 1 ft. 6 in. 



10. Felspathic ash ; altered, from Arenig ; no stria?, no smoothing. 

 Size, 1 ft. 6 in. x 1 ft. 6 in. x 1 ft. 



11. Well-bedded striped mndstone flag, probably of Silurian age. 

 Size, 1 ft. 6 in. x 1 ft. x 3 in. 



12. Fragments of slate showing ice-groovings and smoothing ; 

 probably Silurian blue mndstone from the Berwyn Hills. 



Report upon National Geological Surveys : Part I., Europe. By 

 W. Topley, F.G.S., Assoc. Inst. G.E., Geological Survey of 

 England and Wales. 



Introduction. 



In the following pages a brief account is given of the organisation and 

 publications of the chief Geological Surreys ' in Europe. The statements 

 are taken from official sources, or from an inspection of the publications. 



Information has been kindly supplied by the directors of the following 

 surveys — Austro-Hungary, Bavaria, Belgium, Italy, Norway, Portugal, 

 Saxony, Spain, Sweden, Switzerland ; most of these have since corrected 

 the proofs of the parts of this Report referring to their respective surveys. 2 



In the preparation of this report my colleague Mr. W. H. Dalton 

 has given me much assistance ; my thanks are also due to Professor 

 G. A. Lebour, Mr. "W. Rupert Jones, and Mr. F. W. Rudler. 



The libraries of the Geological Survey (Museum of Practical Geology), 

 and of the Geological and Geographical Societies, contain a large collec- 

 tion of the maps and other publications of the various surveys (see the 

 * Catalogues ' of those libraries) . The more important publications are 

 noted as they appear in the ' Quarterly Journal of the Geological Society ' 

 (November number of each year), the ' Proceedings of the Royal 

 Geographical Society,' and in ' Petermann's Mittheilungen ' (Gotha). 

 The ' Geological Record ' gives descriptions of maps published in and 

 since 1874. 



The official title of the Survey is first given, with the place of the head 

 office, which is also the place of publication unless otherwise stated. 



1 The exact equivalent of the English term ' Survey ' is not used on the Con- 

 tinent ; it is that of Committee, Commission, Inquiry, Institute, or Service. 



1 Some corrections and additions, including those thus supplied, have been made 

 since the Report was read at Montreal. 



