37 
Ami, lastly, they refer the upper red sandstone and conglomerate to the new 
red sandstone, which arrangement they believe to be confirmed by the formations 
on the nearest main land ot Scotland. 
They admit, however, that there are some points of disagreement between these 
strata and their supposed equivalents in many parts of Great Britain, and point 
out in what particulars the dissimilarity consists; and, in connexion with this sub¬ 
ject, remark: “If, therefore, the rocks of the Arran section were assumed as the 
* general type of all contemporaneous deposites, there would then be no serious 
4 objection to a classification attempted by some Continental and British geologists, 
£ wherein all the rocks of the orders above described are considered as belonging to 
4 one great formation of red sandstone, of which the carboniferous series only forms 
4 a subordinate part; for, as we extend our generalizations, we must necessarily 
4 diminish the number of our geological groups. We, therefore, think that this 
« classification may have its advantage in comparing the contemporaneous depos- 
4 ites of remote regions. It is certainly inapplicable to the English secondary 
4 rocks, because the newer red sandstone is there always unconformable to the car- 
4 boniferous, and, therefore, finds its true place in the superior order. This de- 
4 monstrates that the carboniferous order of England was dislocated before the ex- 
4 istence of the next superior order; but all dislocations are probably, in a certain 
4 sense, local phenomena; and, on that account, we do not think that a want of 
4 conformity is one of the elements that will much assist us in grouping together, 
4 or in separating, contemporaneous deposites in distant parts of the earth.” 
They believe even the oldest of the granite to be newer than the new red sand¬ 
stone, and that the trap in the southern part of the island is also newer; as it not 
only traverses the sandstone in many places, but has overflowed it and formed 
mountain masses of overlying rock. It must, therefore, have been in a much more 
fluid state than the granite at the time of the eruption. As it regards the age of 
the trap, it is difficult to conjecture, and it is not improbable that there may have 
been several periods of eruption, as the most of the Hebridean trap is newer than 
the oolitic series, and in Ireland it is posterior even to the chalk. 
In reference to the granite mountains, they hazard the conjecture that the traps 
had their origin below them; and if these eruptive forces were not able to break 
through the thick covering of granite and primary schist, they may have acted on 
them in the mass, have partially penetrated them, and been the very agents by 
which they were elevated to their present altitudes. 
Monday , 21s£.—The first paper read this day in the Geological Section (Mr. 
Lyell in the chair) was 44 on the stratified deposites which constitute the Northern 
and Central Regions of Russia,” by Mr. Murchison, who, in company with M. 
E. de Verneuil, Membre de Societe Geologique de France, had recently visited 
Russia for the purpose of determining, the relations of the older stratified deposites 
in that empire; and he took this early opportunity, in anticipation of a more de¬ 
tailed memoir, to lay the result of their investigation before the public. His lec¬ 
ture being a mere sketch, my notes of it must necessarily be still more imperfect; 
and I shall endeavor only to convey briefly some faint idea of this truly interesting 
