ls2 THE OLD RED SANDSTONE. 
Caithness, and Cromarty, and studied their peculiarities ; and 
yet, on being introduced last year to the discoveries of Mr. 
Webster at Balruddery, he found his acquaintance with both 
the upper and lower groups stand him in but the same stead 
that his first acquired knowledge of the upper group had 
stood him a few years before. He agreed with Agassiz in 
pronouncing the group at Balruddery essentially a new group. 
Add to this evidence the well weighed testimony of Mr. Murch- 
ison regarding the three formations which the Old Red Sand- 
stone contains in England, where the entire system is found 
continuous, the Cornstone overlying the Tilestone, and the 
Quartzose conglomerate the Cornstone ; take into account, the 
fact that, there, each formation has its characteristic fossil, 
identical with some characteristic fossil of the corresponding 
formation of Scotland —that the Tilestones of the one, and 
the lower group of the other, have their Dipterus in com- 
mon — that the Cornstones of the one, and the middle group 
of the other, have their Cephalaspis in common —that the 
Quartzose conglomerate of the one, and the upper group of 
the other, have their Holoptychius in common; and then say 
whether the proofs of distinct succeeding formations can be 
more surely established. If, however, the reader still enter- 
tain a doubt, let him consult the singularly instructive section 
of the entire system, from the Carboniferous Limestone to 
the Upper Silurian, given by Mr. Murchison, in his Silurian 
System, (Part II., Plate XXXI., fig. 1,) and he will find the 
doubt vanish. But to return to the fossils of the Cornstone 
group. 
The characteristic fossil of this deposit, the Cephalaspis, 
occurs in considerable abundance in Forfarshire, and in a 
much more entire state than in the Cornstones of England 
and Wales. The rocks to which it belongs are also devel- 
