104 ALPINE FLOWERS [PART L 



size, decomposing layer by layer, with only a small core of the 

 untouched rock in the centre of each ball. It is a noteworthy 

 fact that basalt in this spheroidal condition weathers and 

 decomposes much more rapidly than it does in the prismatic 

 or columnar state. Eocks such as those we have been consider- 

 ing (with the exception of the grits and quartzite) have all 

 been thrown up in a molten or pasty condition, which precluded 

 their being subject to many of the rules which water-deposited 

 rocks are bound by. Their structure is in a great measure the 

 result of cooling ; and although they frequently have a bedded 

 appearance, they are not under the rigid sway of dip and strike,, 

 which in other rocks is all-powerful in producing, or rather in 

 preparing, the structure of a country. Indeed, in the great 

 majority of cases, it is the advent of the eruptive rocks which 

 has given the sedimentary deposits their present positions, or 

 what is technically called their "lie." Few of the latter,, 

 whether sandstones, limestones, shales, clays, or sands, are 

 now lying in the horizontal positions in which they were formed, 

 especially in much-disturbed and dislocated Britain. Great 

 geological operations have taken place since then, and have 

 squeezed, tilted up, and broken these beds of rock into every 

 shape. And it will be obvious to all that had it not been for 

 these great changes, the edges of these rocks could never have 

 been brought under the influence of rivers and glaciers to carve 

 them on the large scale into hill and dale, and of rain more 

 delicately to "weather" and ornament them. It is therefore 

 very necessary to observe the dip, or general mode of lying 

 of the beds of any district which it is desired to make use of for 

 rockwork purposes. The writer has seen a large rock-garden in 

 the north of England which was laid out with great care and 

 at vast expense, which is spoilt by one apparently small but 

 fatal oversight the dip of the beautifully arranged rockery- 

 blocks is westerly and strongly-marked, while the dip of the 

 real " live " rock immediately beneath is due east. Now this 

 seems a small thing to find fault with ; and it is true that an 

 uneducated eye might be well pleased, in ignorance of the defect. 

 But consider that this easterly dip in that part of the country is 



