



Inches to 



Natural Scale. 



one Mile. 





: 10,000 ., 



... 6-336 





; 10,560 ., 



, .. 6-000 





; 20,000 ., 



,.,. 3-168 





; 25,000 ., 



... 2-534 





: 50,000 ., 



,.. 1-267 





; 63,360 .. 



.. rooo 





; 75,000 ., 



, . . -845 





: 80,000 ., 



•792 





; 100,000 ., 



•633 





: 144,000 ., 



•440 





: 200,000 ., 



•317 





: 400,000 ., 



■159 



448 W. TopJey — European Geological Surveys. 



surface, with their English equivalents. Brief mention is also some- 

 times made of the Geological Surveys. 



In the following pages the natural scale of maps is given, this 

 being the method almost universally adopted on the Continent. The 

 following table gives the equivalents, in English inches, of the scales 

 referred to : — 



Inches to 



Countries. 



Fpper Silesia, Italy (part). 



United Kingdom (part). 



Belgium, Italy (part). 



Prussia, Saxony, Alsace-Lorraine. 



Sweden (part), Italy (part). 



United Kingdom (part). 



Austria and Hungary. 



France. 



Italy, Norway, Switzerland, Bavaria. 



Austria and Hungary. 



Netherlands, Finland, Sweden (part). 



Spain. 

 The meridian adopted for the maps varies much. As a rule it is 

 that of the capital of the country. The exceptions to this are the 

 maps of Germany and some of Norway, where the meridian is Eerro, 

 and Switzerland, where it is Paris. Paris has been taken as the 

 meridian for the map of Europe, now being prepared by a committee 

 of the International Geological Congress ; scale 1 : 1,500,000. Tliis 

 map, in 49 sheets, will be based upon those of the Geological 

 Surveys hereafter described. 



The International Geodetic Congress at Eome, in 1883, recom- 

 mended the adoption of Greenwich as the universal meridian, longi- 

 tude to be reckoned from west to east only. The Congress meets 

 at Washington in October of this year (1884), when the provisional 

 resolution passed at Eome will probably be confirmed. 



On the Continent a large number of official and semi-official 

 l^ublications have been made by Government mining engineers and 

 others, but these are not here included unless they form part of 

 a systematic survey or give the main results of such survey. 



The earliest survey is that of the United Kingdom, 1832. In all 

 its essential characters this is now much the same as when left by 

 its founder, Sir H. de la Beche, and probably no other survey yet 

 rivals it in the variety and completeness of its publications. Many 

 of the more important Continental surveys have been commenced 

 during the last 15 years. 



Much difficulty has been felt in deciding what small general maps 

 should be mentioned. The Catalogues already referred to give the 

 titles of many of them. For the most part those only are here 

 mentioned which are official, or which are known to be reductions 

 of official maps. 



Some interesting results come out from this investigation as 

 regards the relative amount of work done by private and official 

 geologists. In England the foundations of the survey, and in fact 

 of all detailed field geology, were laid by private workers, and a 

 very large proportion of English geological literature has always 



