; 254 | Geological Systems— Geological Maps .&c. 
and structure, which proves the extension and similarity . of 
their formation 
The secondary and alluvial, consisting of the wreck of more 
ancient rocks, vary with the locality and nature of the rocks 
from which they originate, and have nothing fixed or general- 
ly characteristic of a universal formation. Benahdiog on the — 
accidents of declivity, &c., of the foundation on which the 
are placed, without any regular direction of the stratification, 
each basin has its own relative position; and as they touch 
each other at the sides, they are not subject to any over-lying 
stratification that can fix the relative period of their different 
formation. 
Smith, in his Geological Map of England, (if I recollect 
well, for I have not seen it for many years,) places the secon- 
dary of the west on the primitive and transition of the Cum- 
berland mountains, and in the section which he gives, all the 
secondary of the east overlies them, by which he indicates, 
that all the chalk of the east overlies the coal of the west: an 
order on which others have built their theories, and which I 
rather think is not correct. The Vulcanic class is a litle 
more irregular. It certainly alternates with the alluvial and 
secondary, and I think with the transition, so that its formation 
has en coeval with the three Neptunian classes. 
-Perhap: the most useful classification, in the present state 
of the science, would be to retain Werner’s five classes as 
being well defined, that is, as well as the sraduated variety of 
nature will permit, (for one species runs into another by such 
small and imperceptible degrees as scarcely to leave a footing 
for our artificial divisions) and to make some subdivisions in 
each class, without deranging the system already best known, 
or the ideas of those who follow it. Werner, in placing his 
newest Floetz Trap in the secondary class, commits a great 
fault, for these rocks alternate with the alluvial secondary and 
pee % py ud Ain with the transition, and are mostly an- 
ocks. It is probable that the secondary is 
ihe most oticuve class in bis system, for like all system- 
makers he copied what he saw, and the Erzgebirge, the 
field that produced his system, has little or no secondary, but 
with the exception of the newest Floetz pga it is the most 
ida: ne eg ee ae 
Accel 
ppcentese a+ 
