196 Of i H I II I.D-GEOLCX N PART i 



With regard to the superficial deposits of a distri< t. 

 the first aim of the geologist is to gather all available 

 facts, not only from the sections exposed in natural 

 openings, as well as in quarries and other art i final 

 exposures, but, where needful, from the records of 

 well-sinkings, borings, foundation -diggings, and other 

 kinds of excavation. The naming of the deposits, 



FIG. 79. Plan of a peat-moss which has filled up a former shallow lake, except 

 one small patch of water. 



so far as their lithological characters go, will usually 

 be an easy task; but it may be more difficult to 

 determine their relative order of appearance and the 

 circumstances under which each was formed. A few 

 examples of the kind of examination which may be made 

 will here suffice. 



Peat-mosses. These accumulations of marshy vegeta- 

 tion play an important part in the surface geology of 

 many tracts of Western Europe. In endeavouring to 

 ascertain the history of a peat-moss we have first to con- 



