92 
REPORT—1854. 
g re y group,” the “ Middle or red group,” and the “ Upper or yellow group." TV 
grey group consisted of laminated flagstones and rusty-coloured sandstones, with occs- 
sional beds of carbonaceous shales. The second group consisted of red and chocolate- 
coloured sandstones and conglomerates, with beds of cornstone or concretionary lime¬ 
stones ; and the upper group of thick-bedded yellow sandstones and variegated marl*. 
The lower and middle groups w ere typically developed in Forfar and Fife, the upper 
group especially in Fifeshire. In some of the Conglomerates (which were simply cun- 
trrni'nl ntnl i ,.1•! 1 .1 i < • i u ' ''I., t la * 
in the 
liich 
solidatcd grovel anq shinglej there were, he thought, evidences of * r iec drift ’ 
smoothed and scratched boulders, particularly in their peculiar aggregation, »"..■> 
was strictly analogous to the piling up of shingle and gravel and clays on the Arctic 
shores, us described bv Delta and other Arctic vovagers. Palfflotitolwgicwlly, the lower 
or grey group wns characterized by abundant terrestrial vegetation, by Jchthvolitw, a* 
the Cheiracantluis, Ostcolepis and other spirit-finned fishes described by Prof. .Agassi*, 
and by crustacean remains, ns those of tno Fierygotus ami other undcicrilwd ic mI - 
ey'ed genera. The red group was entirely void of vegetables, ntid characterized mure 
especially by the Ofiphalaspis, CoccoBteu- and other bony-cased fishes; mil the tipper 
or yellow group by such fishes as the Holoptycliius, Platt giiatlius, and other ordinary 
tinned fishes. With regard to the carboniferous system, as developed in Scotland, no 
proposed to divide it into three or four great groups:— 1st, “ Tint lower co.d-mca- 
sures;" 2nd, “The mountain limestonej" 3rd, “The millstone grit;" and, h", 
I he upper or true coal-measures.” The lower group, mineralogically speaking, 
consisted of thick white bedded sandstone (Craig! oil?) and St. Andrew’*) beds of arc 
i- ’ thin scams of coal, and peculiar beds of freshwater or estuary limestone 
tins limestone being thick and compact as at BnrdiclialWe and Burntisland; or Hon, 
and entirely composed of shells, as in the east of F jfeshire. The mountain hmeV.oiu-, 
noil'- 1 not 80 fully developed us in Derbyshire and Yorkshire, was yet characterize.! 
by the same mnrm 2 (basils, viz. corals, testacen, and fi Aw. The millstone gnt «« 
^d > J^ P ( Cr / e } : J'r 0Velni ’ l ‘ d; bul t’te ‘rue or upper coal-measures were fully deve '»pej 
nrnl imr 8 8 ^f ,0ff r t,UCnl of snnddone*, fire-clays, shales, cools, ironstonej 
In.- .L- P ,i 1 T 8toncs n,jt containing t ncrinites or murine fossils. Pal.xou ologt«J 
s one ht ,V ", ^° UP WlH Wdl off by the marine beds of the vcflow - 
«one beneath and the mountain marine limestone above. Us ovgm iz«t-»'; 
I “ Z « tUBr y “Wler, and, though containing many of the same vcfictab!« » 
mm. o. : r ■ nU ' UMl, ' Cflj 1,0 ‘''ought they indicated frequent specific distinctions.J 
2£. r°^ ", aB 1,1150 w, 'll defined, whether ill its shales or 
enoET , C 'Vr s ! ri r tly ' naril,u in character, and not to be mistaken; 
The mSbl 1 - ‘ Pn " ,Uctu <S Terchrntiilic, Spirifc-r, &c., midoccasionul lnM* 
shells jiiidf “"d upper coal-measures, though containing bands o( a” 1 . 
StSnmr 1 T .°f l ' e M ^ alic . 1,,h >»- principally characterized I* 
Heftrictiim , . ri0 ’^ f n ‘*» Cidainitfs, and other plants which mark all tiue coi 
some « ‘’ 8 er ‘ mi< i , tlK o fl bove described, he avoided the ](1 
S whic] ' n l'f earef l to belong to the Penman; hr^^ 
car/joni('erou* ° T' ’ 111 l ' ust * tke following subdivision of thejdd red " w,lds . flIf _ 
I ir m ^ ; L upper coal measure; ->• 
middle or "S ?T * nt S '• lwwe '- l '°al-measurv8. Dreo»i*n : l’ppCr 
i rid group; lower, or grey erouu Adootin® the maxim that the 
te,".?* •',.«« ™',i, C fti.*., Mr. ’ffi* 
red sandstone on!j 0l . , | by the adoption of the “ Yellow group j 
British deposits ^ ** ^ owcr c °ah measures” into the published classi 
On the Structure and Tenure of Stratified Itochs, as a means of d,term"* 
te Cot ^^ns under which they are formed. By D- Page- 
Thurso. 
