36 CO. Lapworth—Recent Discoveries in Sweden. 
are the author’s “Strata with Jonograptus colonus, Barr.” They 
consist as a rule of grey or greenish, irregular, tolerably thick-bedded 
and often calcareous schists, with obscure traces of fossils. The 
commonest form is Monograptus colonus, Barr., M. sp. nov. resembling 
I. concinnus, Lapw., and one or two additional species. 
The most characteristic fossil of these beds, however, is Cardiola 
interrupta, Brod. These “Colonus beds” are easily distinguished 
from the underlying strata by their physical peculiarities, and are, 
according to Linnarsson, in all probability the highest Silurian strata 
in Scania. He believes that they are of younger age than any of the 
Silurian beds of Westrogothia and Dalarne. Many of the fossils of 
the “Strata with Jf testis,” and the ‘Strata with JZ colonus,” are 
met with in the Riccarton beds of the South of Scotland, and with 
these, rather than with the certainly older Gala group, the author is 
inclined to parallel them. 
With respect to his so-called Lobiferus-Beds, I am inclined to 
think that they are of much greater systematic value than Linnarsson 
is apparently willing to consider them. To judge from the specimens 
of these beds I have actually seen, I am inclined to parallel their 
most prolific zone with the base of Upper Birkhill or top of Lower 
Birkhill, where the true JL lobiferus of M‘Coy is abundant and 
characteristic, as indeed are all the fossils of the typical Lobiferus beds. 
There are, however, in the British Valentian or Llandovery rocks 
great thicknesses of fossiliferous strata both above and below this 
special horizon. It is not unlikely that the Brachiopod Schists stand 
in the place of the Lowest Llandovery, and therefore of the lowest 
beds of the Birkhill. But where is the Swedish representative of the 
great Gala group of South Scotland and the Tarannon of Wales ? 
This highest Valentian formation swarms with what may be called, 
for the sake of illustration, varieties of JZ lobiferus, such as J. 
exiguus, Nich., and Jf. Becki, Barrande. These occur in millions 
in the Gala Group and the Tarannon of North Wales, with a slight 
intermixture of true Wenlock forms, such as Retiolites Geinitzianus 
and Monograptus priodon. I am at present inclined to the opinion 
that the Swedish geologists will find these 'Tarannon beds in the 
highest stages of their Lobiferus Schists, as well as in the grey 
M. Crispus shales of Tosterup. I look forward with confidence that 
in the event of their discovery, they will be found to be characterized 
by similar lobiferous species. 
Linnarsson’s discovery of the Zone of Cyrtograptus Murchisoni in 
Sweden is indeed a matter of great interest. This zone, never many 
feet in thickness, forms the basal bed of the Wenlock formation in 
Britain. J have traced it at the base of the Wenlock of Builth, in 
Shropshire, in North Wales, and in the Lake District, holding 
invariably the same stratigraphical position, and affording precisely 
the same fossils. This enables us to fix the immediately superior 
Swedish strata as of true Wenlock age. 
Though I know of at least two newer zones in the Wenlock- 
Ludlow or Salopian strata of Britain, I have never recognized any- 
thing that can be strictly paralleled with Mr. Linnarsson’s Zone of 
Monograptus testis, Barr. 
