450 
ELEMENTS OE GEOLOGY. 
in all main points it agrees with the table drawn up in 1864 
for the sixth edition of my “Elements.” Mr. Etheridge* has 
since published- an excellent account of the different subdi¬ 
visions of the rocks and their fossils, and has also pointed 
out their relation to the corresponding marine strata of the 
Continent. The slight modifications introduced in my table 
since 1864 are the result of a tour made in 1870 in company 
with Mr. T. McK. Hughes, when we had the advantage of 
Mr. Etheridge’s memoir as our guide. 
The place of the sandstones of the Foreland is not yet 
clearly made out, as they are cut off by a great fault and 
disturbance. 
Upper Devonian Rocks.—The slates and sandstones of Barn¬ 
staple (a and d of the preceding section) contain the shell 
Spirifera disjuneta^ Sow. {S, 
'Verneuilii^ Murch.), (see 
Fig. 508), which has a very 
wide range in Europe, Asia 
Minor, and even China; also 
Strophalosia caperata^ to¬ 
gether with the large tri- 
S'piriferadi8junctxi,^o\w. Syii.Fdmem’Zw, lol)ite JPhaCOpS lotifrons^ 
Murch. Upper I)evouiau.Bonlog„e.^ Bronil. (see Fig. 509),‘which 
is all but world-wide in its distribution. The fossils are nu¬ 
merous, and comprise about 150 species 
of mollusca, a fifth of which pass up into 
the overlying Carboniferous rocks. To 
this Upper Devonian belong a series of 
limestones and slates well developed at 
Petherwyn, in Cornwall, where they have 
yielded 75 species of fossils. The genus 
of Cephalopoda called Clymenia (Fig. 
510) is represented by no less than eleven 
species, and strata occupying the same 
position in Germany are called Clyme- 
nien-Kalk, or sometimes Cypridinen- 
Schiefer, on account of the number of 
minute bivalve shells of the crustacean 
called Cypridina serrato-striata (Fig. 511), 
which is found in these beds, in the Rhen- 
ish provinces, the Harz, Saxony, and Sile- 
sia, as well as in Cornwall and Belgium. vonian in Europe, Asia, 
Middle Devonian Rocks.—-We come next 
to the most typical portion of the Devonian system, including 
the great limestones of Plymouth and Torbay, replete with 
* Quart. Geol. Journ., vol. xxiii., 1867. 
Fig. 509. 
