REPORT OF MEETINGS FOR 1902 231 



The subsidence went on, perhaps intermittently, until, in 

 the English Lake District, what had been the shore line at 

 the commencement had been carried nearer to the centre of 

 the Earth by some twelve or more thousand feet. 



Then, as we learn from the Scottish records, which are 

 much clearer upon this point than the evidence obtained 

 elsewhere, oscillations of level began to set in, and eventually 

 the net results of the movements assumed an upward tendency. 

 Continental conditions began to take the place of oceanic, 

 and in course of time the elevation of the old sea bottom 

 extended so far that the rainfall of these parts was reduced 

 to so much below that required fur the needs of vegetation 

 that desert conditions set in, and it is probable that they 

 remained here for a period of great length. 



It was under these conditions that the red strata which 

 succeed the Ludlow Rocks were found. I have called these 

 the Lanarkian Rocks, because what remains of them is best 

 seen in Lanarkshire. In the Survey Memoir they are referred 

 to as Downtonian — a term, by the way, which had previously 

 been used for the Middle and Upper Ludlow Rocks. 



The upheaval of the old sea bottom gave rise to two 

 important effects, both of which can be realised by a simple 

 experiment which the reader is recommended to try for 

 himself. Get a few strips of linoleum, or some leathern straps, 

 or any other similarly flexible material of moderate thickness. 

 Mark the edges of every other strap some distinctive colour — 

 chalks will answer the purpose very well. Then lay the 

 straps one upon another, lengthways, upon any smooth 

 surface, such as the polished top of a table. Put a weight 

 upon one end of the pile, and then grip the other end and 

 press it towards the weight. The effect will be that the 

 straps will be thrown first of all into an upfold of a simple 

 character ; but if the pressure is managed carefully it will 

 be quite easy to make the straps fold so that there shall 

 be more than one or two bends. If the process of lateral 

 compression is continued, the folds will become more and 

 more compressed, and the upper surface of the pile will rise 

 concurrently to successively higher points above the level of 

 the table. Note, further, that the rise will be greater over 

 the upfolds than over the correlative dowufolds betweeii them. 



