DEPOSITS OF SCOTLAND. 381 
the fossils, — restricted very much to the gray sandstones of 
the deposit,—are of an entirely different group. Here, as 
in the immensely developed Cornstones of England, the pre- 
vailing and most characteristic organism is the Cephalaspi's ; 
which has now been found in Forfar and Kincardineshires by 
Sir Charles Lyell, Mr. Webster, and others; in Sterlingshire by 
our ingenious brother member Mr. Alexander Bryson; and in 
Ayr by the late Dr. Brown of Longfine ;—all the specimens, 
however, in the same gray beds of micaceous sandstone, repre- 
sented by what is known as the Arbroath pavement, which, 
like the red deposits that lie over and under them, run from 
side to side of the kingdom. While the fossils of the Lower 
Old Red Sandstone are more adequately represented in my 
collection than those of any other Scottish formation, the fos- 
sils of this Middle Old Red are almost the least adequately 
represented. And in this respect it resembles every other col- 
lection yet made, except that of Mr. Webster, now, I under- 
stand, in the possession of Lord Kinnaird. There is perhaps 
no Scottish formation in which the Palontologist has still so 
much to do as in this Middle Old Red Sandstone. Our respec- 
ted President Dr. Fleming called attention, a full quarter of a 
century ago, to some of its plants, and again took up the sub- 
ject no further back than last year, in an interesting paper read 
before our Society; and Agassiz has figured and described 
some of its fishes, and more partially and incidentally, at least 
one of its crustaceans. But much still remains to be done. 
From what I have seen of Mr. Webster’s collection, I should 
infer that materials have been already accumulated sufficient 
for the restoration of its great crustacean, —one of the most 
gigantic of its family, whether recent or extinct; and, as the 
Den of Balruddery has furnished of itself nearly a hundred 
specimens of Cephalaspis (still a comparatively rare ichthyo- 
lite elsewhere), most of which are now in the hands of Lord 
