30 
such as variations or irregularities in the surface, or subor- 
dinate basins, or ridges, they could be introduced by means 
of small cross sections, in such a way, that the whole method 
was reduced to two simple operations. The strata having 
been delineated on the wood, it then became the province of 
in a workman to put the material together, to form the wood 
the proper shapes, and the whole must be afterwards painted, 
under the superintendence of a draftsman. Upon the 
surface objects were painted as on a map. The information 
given by a model like this was varied. It contained infor- 
mation from the pits in different places. The various steep- 
ness of the strata it was almost impossible to bear in mind ; 
but when the various known points were reduced to shape 
in this manner, the rest of the work assumed a degree of 
' probability which could not be attained without a model. 
This model was the first attempt of the kind, and, notwith- 
standing the difficulty of instructing the workmen, for the 
first time, the whole expense, including the case, was not 
more than ^28 or ^30. That cost was trifling, compared 
with the interest of the subjects represented ; and he con- 
ceived that it was deserving of the attention of this Society 
to attempt to form similar models of the districts, or por- 
tions of the districts, in which they reside. He was not 
aware of anything that could give greater interest to geolo- 
gical study than such models ; and many gentlemen of ex- 
perience had expressed the opinion, that the more frequent 
construction of such models would tend greatly to the in- 
crease of geological knowledge. Geology, at the present 
time, was a science of facts. They had now arrived at the 
extent of knowing their ignorance. When first Geology 
attracted attention, it was a science of theory. Theories 
were propounded in which the formation of the world was 
attempted to be explained : some saying that fire, and some 
that water, had been the principal agents employed by the 
