374 Geological Maps. [ July, 
Fortunately for the farmers, they have a powerful ally in the 
opacity of even superficial formations; and the reflecting geologist 
is no doubt often staggered at the hardihood of surveyors who 
draw a wriggling line of outcrop to a stratum which is known to 
be buried fifty, a hundred, or more feet beneath drift-deposits, and 
beyond the ken of mortal men. 
Much may be said, no doubt, on the part of the surveyors, 
who, to do them justice, are really not in the habit of mapping the 
outcrops of strata without some tangible warrant for so domg. If 
a given series of beds is observed where properly exposed to 
“behave” in a particular manner towards those above and below 
them, and towards the “form of the ground,” it is reasonable to 
infer that they will do the same at a short distance, although they 
may not there be seen at the surface. Thus the geological sur- 
veyor has to take note of the most trivial circumstances that may 
be within the reach of observation, so as to decide for future 
guidance what phenomena are general and what accidental. In this 
manner, a roadside bank speaks volumes, and a ditch reveals wonders, 
while a railway-cutting affords an opportunity of luxurious survey- 
ing, which ought to stimulate the surveyor to take a sanguine view 
of the prospects of all projected lines. 
After all, the fact remains, that perhaps the greatest desidera- 
tum in British geology is a good map of the surface-deposits of the 
United Kingdom. We have several first-rate geological maps (in 
the ordinary sense) of England and Wales, and of them all, the 
most generally useful is no doubt Professor Ramsay’s beautiful 
sheet, the geology of the new edition of which is much improved, 
while the actual and ideal sections have required no change. ‘The 
new edition of the Greenough Geological Map is probably the most 
accurate yet published, so far as the wretched topography of most 
of it will allow of geological precision ; indeed, it embodies the 
whole of the information in the possession of the Geological — 
Survey, and the Council of the Geological Society, almost up to the 
date of publication ; at any rate, that portion of it which was con- 
sidered sufficiently authentic to be published. 
The only reliable geological map of Scotland, at present in 
existence, is the small one by Sir R. I. Murchison and Mr. Geikie ; 
that is to say, if the views held by the great majority of geologists, 
in opposition to Professor Nicol, are correct. This map leaves yery 
little to be desired except surface-geology and a larger scale; and 
we hope that when anew edition is called for, the scale will be 
increased. Of Ireland, the old map of Sir Richard Griffith and the 
small reduction of it still remain the best ; but we hope they will 
soon be superseded by a map compiled by one of the officers of the 
Trish Survey, for that survey must necessarily have modified our 
knowledge of the distribution and limits of the several geological 
formations in that island. 
