REPORT OF THE MEETINGS FOR 1900 229 



were originally beds of marine sediment, alternately sand, 

 sandy mud, and clay, deposited upon an ancient sea bottom 

 while the land was undergoing a very slow subsidence. 

 This event dates back many millions of years in the past, 

 long prior to the first appearance of any but the very lowest 

 forms of life now living upon the earth ; and, of course, 

 long before any geographical features now anywhere in 

 existence had come into being. Geologists find it convenient 

 to give distinctive names to great groups of rocks, and those 

 in question belong to the Silurian Period, and to that early 

 part of it which is typically represented by the rocks 

 near Gala, whence the name Gala Rocks is now usually 

 applied to those oldest rocks which form the northern part 

 of Berwickshire, and which extend south-westward, forming 

 the southern uplands of Scotland, to the coasts of Galloway 

 and Carrick. 



Near the close of the period, and after the oldest rocks 

 seen at Burnmouth had been buried beneath a pile of 

 sediments of much the same kind, some eight or ten 

 thousand feet in thickness, a slow upward movement of 

 the eaith's crust set in. The old sediments, at first buried 

 thousands of feet below the surface, after being slowly 

 compacted into hard rock, were gradually squeezed from 

 their original state of a pile of horizontal sheets of sediment 

 into a series of folds — a process which one can readily 

 imitate on a small scale, and in a few seconds, by placing 

 two or three leathern straps one on the other, and then 

 pressing the opposite ends towards each other. If the 

 expeiiment is performed carefully it will be easy to bend 

 the straps first into one simple fold, and then by continuing 

 the process to end by plicating the straps into a series 

 of puckers of any degree of complexity. Lateral pressure, 

 steadily applied, through long millions of years, to the 

 old sediments under notice, first gently arched them upward, 

 raising them gradually above sea-level, and ended by 

 crumpling the whole mass into a puckered and highly- 

 convoluted series, in which condition these Gala Rocks may 

 be seen along the Berwickshire coast now. Several important 

 results ensued as a consequence of this crumpling and 

 upheaval of the old Silurian sediments. At an early stage 



