J. G. Goodchild — The Paste of Limestones. 73 



however, in some of the dry regions in the interior of North 

 America, just where we might expect to find it on Richthofen's 

 theory. 



I maintain, therefore, that upon meteorological principles a very 

 dry climate in Central Europe was the necessary and inevitable 

 result of the great spread of glacier-ice over Scandinavia and the 

 British Isles, inasmuch as it practically shifted the. coast-line from 

 the shores of Prussia and Holland to the westward of Britain and 

 Ireland, at the same time interposing a powerful condenser of 

 atmospheric moisture between Central Europe and the open water 

 of the North Atlantic. If this opinion be correct, it is evidently 

 a mistake to call the Loess " post- Glacial." The character of the 

 fauna it contains is indeed decisive upon this point, for, as Mr. Belt * 

 insisted, "no more Arctic fauna is known in the basins of the 

 Danube and the Rhine than that of the Loess." It seems likely, 

 however, that as the Scandinavian and British ice grew and 

 gradually occupied the basins of the Baltic, the German Ocean, and 

 the Irish Sea, the precipitation of snow would be more confined to 

 the west, and the glaciers of the north side of the Alps and of 

 Central Europe would diminish for want of supplies. Therefore 

 a considerable shrinking would take place in the latter region 

 during the Loess period, and large tracts formerly covered by the 

 ice would be laid bare ; for, owing to the dryness and consequent 

 clearness of the air, the sun in summer would be strong and brilliant, 

 and the snow and ice would melt much faster than it could form 

 again. The Loess would therefore succeed the Glacier in those 

 parts, and would cover the beds of Boulder-clay and Gravel which 

 the ice left behind it, and we might conjecture that in Central 

 Europe the succession of stages would probably be as follows : — 



1. A cold moist climate with the formation of peat and lignite 

 beds, indicating the coming on of the ice (Eleplias meridional) s). 



2. The ice in possession of the surface, corresponding to the 

 " Lemming stage " of Dr. Nehring. 



8. A cold dry period with a climate like that of South Siberia, 

 and a Steppe-fauna, resulting from the spread of the ice to 

 the N.W. and its shrinkage to the S.E. 



VI. — The Paste of Limestones. 2 

 By J. Gi Goodchild, F.G.S., H.M. Geol. Survey, 

 Lecturer on Geology and Mineralogy at the Heriot-Watt College. 

 "VTOW that so close attention is being given to the microscopic 

 _Li investigation of rock structures, it is somewhat remarkable 

 that no one should yet have questioned the validity of the views 

 currently received regarding the exact constitution of limestone. 

 Taking account only of those limestones whose original structure 

 has not been obliterated by subsequent changes, the general view is 



1 Quart. Journ. Sci. Jan. 1887, "On the Loess of the Rhine and the Danube." 



2 Founded on communications to the Royal Physical and the Geological Societies of 

 Edinburgh. 



