934 DR ROBERT CAMPBELL ON 
than a normal Old Red Sandstone type of sedimentation. In Kincardineshire, just as 
in the Southern Uplands, the Downtonian rocks form what is truly a transition series, in 
some respects exhibiting the characters of a typical Upper Silurian group of sediments, © 
in others those of the Lower Old Red Sandstone. To the former belong the green and 
grey mudstones and the greywacké-like sandstones; to the latter, the coarse con- 
elomerates and the false-bedded ochreous sandstones. 
Consideration of the paleontological evidence cited above leads to a similar 
conclusion. Neither Dictyocarts nor Ceratiocaris has hitherto been met with in rocks 
younger than Upper Silurian, while both are common forms in the Downtonian else- 
where in Britain. The unique fishes of the Downtonian of the South of Scotland, it is 
true, have not so far been found ; but, since the nature of the invertebrate fossils favours 
the reference of the ‘“‘ Stonehaven Beds” to that horizon, the occurrence of Cyathaspis, 
as Dr Traquair has pointed out, may be regarded as corroborative evidence. 
Professor Kiar* has recently announced the discovery of a Downtonian fauna in 
the sandstone series of the Kristiania area—a series described as Old Red Sandstone by 
Morcuison in 1844, and so regarded by most Norwegian geologists since his time. 
The list of fossils given by Professor K1#r in his preliminary report includes 
Dictyocaris (very abundant), Ceratiocaris sp., at least two new species of Hurypterus, 
Pterygotus sp., two new Cephalaspidomorph fishes, and three new genera of Anaspid 
fishes. 
There is undoubtedly a striking similarity between the above assemblage of fossils 
and those found at Stonehaven. It is impossible, of course, to compare the eurypterids 
and fishes of the two areas until fuller descriptions are available, but in both cases 
there is a noteworthy abundance of the problematical Dictyocaris along with fragments 
of Ceratiocaris. 
In short, the palzeontological evidence and the character of the sedimentation 
together show conclusively that the ‘“‘Stonehaven Beds” must be regarded as Down- 
tonian, although not necessarily on the same horizon as that of the fossiliferous zones 
of the Downtonian rocks of the South of Scotland. 
VII. Comparison oF THE KINCARDINESHIRE DOWNTONIAN WITH THE DoWNTONIAN 
OF THE SOUTHERN UPLANDS. 
The paleontological evidence t obtained in the Southern Uplands indicates that the 
green and grey mudstones, the greywackés, and the fish band are marine. They 
have yielded species of eurypterids, which in the Wenlock series are associated with 
graptolites, in the Ludlow series with a Lingula ; they contain, moreover, Glauconome, 
Spirorbis, crinoid stems, and sponges. The rock types resembling the Old Red Sandstone 
sediments, on the other hand, have been supposed to indicate fresh- or brackish-water 
* Videnskapsselskapets Skrifter, i. Mat.-Naturyv. Klasse, 1911, No. 7. 
+ Mem. Geol. Survey: Silurian Rocks of Britain, vol. i. pp. 69, 603. 
