8 
are of great thickness, and are now elevated by the earth's 
expansion into lofty mountains ; consequently the thickness 
of these above the level of the sea will afford a minimum 
amount of the earth's expansion, those beneath the surface 
not being reckoned since they are not visible. These primary 
systems are the Cumbrian (grauwacke), and the Silurian 
(Welsh). 
Ascending from the primary strata up to the secondary 
series, are there any traces of the expansion of the 
earth's crust, or the increase of its orbit? The lowest 
portions of the secondary strata are 1st: — Old red sandstone. 
2nd. Mountain or carboniferous limestone. 3rd. Millstone 
grit. 4th. Coal beds. 
a. The old red sandstone by its thick beds of conglomerates, 
consisting of rounded pebbles, boulders, and coarse sand- 
stone, prove that decided upward movements from the bottom 
of the ocean had then commenced, (Phillips, vol. I, p. 175.) 
"The Northern Ocean was then studded with islands, 
" bounded by shores, supplied by inundations from extended 
" land ; the amount of these is demonstrated by the abun- 
" dance of arenaceous and clay sediments, plants, and thin 
" beds of coal." The old red sandstone is of great thickness 
in Devonshire and in Scotland ; the three systems called the 
Cumbrian, Silurian, and Devonian (collectively the Palaeozoic 
rocks) are of vast thickness, not less in England than 30,000 
feet, so that even before the mountain limestone we have 
indubitable evidence of six miles expansion, or at least 
10,000 yards. 
b. The mountain limestone was formed in the deeper waters 
of the ocean as a chemical precipitate, and Professor Phillips, 
in his quarto work on the geology of Yorkshire, asks " By 
" what agency was this limestone formed ? By some liquid 
" or gaseous substance generated in the bowels of the earth, 
" and diffused by many openings on its bed." Here then is 
