1874.] Geological Survey of the United Kingdom. 55 
stratigraphical relations of the rocks, their characteristic 
fossils, and notes on the mines and minerals accompany 
most of the maps. Special memoirs on large areas, and 
detailed descriptions of fossils have also been published. 
From three to four thousand square miles are annually 
surveyed in the United Kingdom. There is, however, 
much old ground to be gone over in mapping the superficial 
deposits, which not only have an important economic value 
in many instances, but are also intimately connected with 
questions of health, of drainage, and water-supply. 
The Museum at Jermyn Street well illustrates the appli- 
cations of geology, by exhibiting a series of rocks and 
minerals, and their adaptation to purposes of use and 
ornament. An extensive paleontological collection likewise 
illustrates the geological maps ; the study of fossils proving 
an important guide in the identification of strata. 
It is by studying the Maps, Se¢tions, and Memoirs 
together, that the great practical value of the Survey is 
understood. The Maps themselves will show the superficial 
extent of the different strata, whether gravel, sand, clay, 
limestone, slate, sandstone, marl, or alternations of these 
rocks, such as clay and limestone, sand and gravel. The 
colours representing these geological formations are an 
indication of position and age. To learn their thicknesses, 
mineral characters, &c., the Memoirs must be consulted; 
while to understand their underground extension, the 
Sections will prove necessary. 
Hence the applications to Agriculture, Engineering, and 
ArchiteCture, and still more to Mining, will be at once 
apparent. 
It is needless to remark upon the fruitless trials for coal 
which have been made even in recent years. The late 
Professor Jukes has stated that the money wasted in such 
searches, of which he had been personally cognisant, could 
not have been less than £150,000. The Geological Survey 
has checked much of this fruitless expenditure. 
Some of the more important results of the Survey are 
shown in the Report of the Royal Coal Commission. The 
area of the exposed coal-measures of England is estimated 
at about 2840 square miles. The investigations of Professor 
Ramsay have led him to conclude that 3141 square miles of 
coal measures are present beneath the Permian and Triassic 
strata—301 square miles more than the area of our exposed 
coal-fields ! 
