GEOLOGY, 



THE EARN VALLEY: 



An "Ancient" and "Modern''' Level of the River Earn. 



By F. SMITH F. G. S. E. 



IN the Scottish Naturalist for 1874 will be found a paper on 

 the " Earn Valley " in two parts, accompanied by a map 

 and a plate of sections. This paper treated of the River Earn, 

 and certain deposits that form a lower and a higher " haugh," 

 that were declared to be the newest geological formation 

 in the valley, and to be entirely the work of the river. Rivers 

 are common things, and haughs are so frequently found in the 

 valleys through which they run, that they are considered to be 

 somewhat elementary in their construction, and the mere 

 supernumeraries of strata looking for a place in the geological 

 system, and therefore a little beneath the notice of the 

 matured observer. And yet, curiously enough, it does not 

 seem to be a settled question as to whether the higher haughs 

 were formed by the rivers in their present position or no. 



When this subject (after making new observations) was 

 placed before the Geological Society of Edinburgh, this question 

 arose in discussion ; and it was then kindly explained to me 

 by David Milne Home, Esq., LL.D., who occcupied the chair, 

 that it was the generally received opinion that the higher haugh 

 simply denoted a higher flooding power of the river, and that no 

 alteration in the level of the stream had taken place ; and 

 advised me to prosecute further examinations, as it was an 

 interesting question that had been for a long time unsettled. 



I had most distinctly and unhesitatingly spoken of the 

 a?icient and modern levels of the stream, and had been led by 

 the most unbiased observations so naturally to do this, that 

 the question on this head took me altogether by surprise. I 

 have unfortunately had no opportunity of exploring the valley 

 towards its upper end, as I had hoped this summer to do, but,, 

 so far as the portion of valley considered in the Scottish 

 Naturalist is concerned, I will endeavour to show why I so 



