_Maclure on Geology. 213 
(although small) from the horizon; the cement is in greater 
quantities in proportion to the particles cemented than in any 
of the secondary aggregates, &c. &c. 
The character of the secondary is a horizontal position, that 
perhaps does not admit of the same facility of examining the 
relative situation of its stratification. The compact limestone 
is, probably with reason, considered as the lowest of the sec- 
ondary formation, and always under the coal formation, but it 
appears to me that the secondary is deposited in basins along- 
side of one another, and that each basin has a different order of 
‘Superposition, according to the nature of the agents employed 
in the deposition; that it is a partial, and by no means a gen- 
eral deposition. The secondary aggregates of sandstone and 
Portion 
I am therefore inclined to think, that in geology the best mode 
for the greatest part of the secondary would be to give the rel- 
ative Position of the strata of each valley or basin: and I am 
tather of opinion that they would all differ from one another. 
The French and English basin having chalk for the lowest 
stratum, which has occupied the geologists of both countries for 
these 1Q or 15 years, is perhaps the best known; yet they do 
not know the relative position of the chalk and coals, because 
coals have not been found in the same basin with chalk: coals 
occupy basins filled with different kinds of rocks, and haye no 
resemblance to the rocks found covering the chalk. 
particles together, become rocks, and may alternate in all pro- 
rtions. 
