GLEANINGS 
!N 
SCIENCE. 
JYo. 14 . — February, 1830 . 
I . — Directions for the Guidance of those desirous of making Geologi- 
cal and Miner alogical Observations. 
In considering- tl\e great interest which is attached to geological enquiries, and the 
wide field which is open to the observer in this part of the world, we cannot but 
think that many would be disposed to assist in the collection of the necessary facts, 
were they aware how very simple and elementary the knowledge is which would 
enable them to do so. With little of technical knowledge, beyond what one of or- 
dinary intelligence may very easily acquire, it is in the power of a faithful observer 
to co-operate materially in laying a foundation for a sound and philosophical theory 
of the earth. In Europe much has been done to approximate to a full and correct 
description of geological appearances as they are ; the first step towards attempting 
an account of what they have been. But Europe is a small part of the world, and 
though it be probable that the study of the geology of even that limited portion of 
the globe will not lead to any very erroneous assumptions, as to its general history, 
still we must remember that this is hut a probability, undone, the truth or falsehood 
of which cannot be established without a greater or less accumulation of facts from 
all parts of the world. And even were we quite certain of the universality of all the 
facts of this science, it would still be a question, whether there could be too many 
observers, particularly in one which, like this, is in its infancy. When, however, we 
know that the contrary is the case ; that very many curious facts are found to be of 
local and partial occurrence ; when we see that many of the links wanting in one 
country to the chain of geological evidence are to be sought for in another ; we can- 
not deny but that the progress of geology would be considerably accelerated by a 
general and simultaneous effort on the part of our countrymen scattered over the 
eastern world. Though there maybe few amongst us capable of emulating a Cuvier, 
a Smith, or aBuckland, we must not infer that our efforts would be, therefore, use- 
less. Every fact, however trifling or unconnected it appear to the superficial obser- 
ver, has its value ; and every man possessing ordinary pow r ers may be the recorder 
of a fact, however incapable of generalising or constructing a theory. 
With such views, and in the hope of inducing some of the many whose leisure and 
opportunities will'allow of tli„eir adding a stone to the geological edifice, we gladly 
avail ourselves of the permission of a friend to publish the following clear and ele- 
mentary instructions compiled for the use of the officers attached to the Ordnance 
Survey now' in progress in Ireland. A few trifling and merely verbal alterations 
have been made, simply with the view of adapting the instructions to our readers, 
and rendering them of more general application. 
The first object of a person desirous of collecting geological information should 
he to obtain a general idea of the nature of the rocks which prevail in the tract un- 
der examination; and if they are in strata or beds, of the alternation and super-po- 
sition of these strata with each other ; and also their dip or inclination to the hori- 
zon, and the direction or bearing in which they cut it ; in order to judge wdien the 
same beds may again probably come to the surface, since they often preserve the 
same plane over a considerable extent. 
It is almost needless to observe, that the beds of rivers, cuts for roads, cliffs and 
quarries, are the situations where such observations can, in general, best be made, 
particularly the latter, since the fresh fracture of the sound unaltered rock is there 
exposed, and in some kinds of rock the change taking place from decomposition 
extends to a considerable depth, sometimes of several feet. 
