32 O. Lapworth—Recent Discoveries in Sweden. 
Rocks proposed by Linnarsson was as follows, in descending suc- 
cession :— 
12. Upper Graptolite Schist. 
11. Brachiopod Schist. 
10. Trinucleus Schist. 
9. Chasmops Limestone. 
8. Middle Graptolite Schist. 
7. Orthoceras Limestone. 
According to Angelin’s previous classification, Nos. 8 to 12 were 
merged in the single group of the Clay Schist Series, No. 7 was his 
Oland Limestone, and Nos. 2 to 6 were all lumped together under 
the general name of the Alum Shales. 
Dr. Térnquist, in the year following, very properly proposed to do 
away with the titles of Graptolite Schist, and name these formations 
after their characteristic genus. The Zower Graptolite Schists be- 
came the Phyllograptus Schists, the Middle Graptolite Schists were 
altered to Dicranograptus Schists, and the Upper Graptolite Schists 
were broken up into the two formations of the Lobiferus and Retiolites 
Schists. 
In the present paper, Linnarsson gives a complete résumé of the 
results of his careful study of the details of the succession of the 
various Graptolite Schists during last summer. ‘The following is a 
condensed summary. 
1. Lower Graptolite Schists (or Phyllograptus Schists). 
Under this name are included all the Graptolite-bearing strata that 
lie between the Ceratopyge and Orthoceras Limestones. 'They form 
a single zone of shale or laminated beds of dull dark colours, varying 
from greenish-grey to black. The Graptolite fauna has everywhere 
the same general character, consisting almost universally of various 
genera of the great family of the Dichograptide, and its closest ally 
the Phyllograptide. The commonest genera are Didymograptus, 
Tetragraptus, Dichograptus, Temnograptus, Phyllograptus; and the 
most abundant species are identical with, or representative of, those 
familiar to us in the Skiddaw and Quebec Groups—such as Didy- 
mograptus patulus, Hall, constrictus, Hall, indentus, Hall, etc.; Tetra- 
graptus quadribrachiatus, Hall, T. Bryonoides, Hall, and T. Bigsby, 
Hall. Dichograptus is rare, but Phyllograptus is occasionally abundant. 
The author points out the identity of this fauna with that which is 
characteristic of the Arenig in England, Wales, and Canada. 
2. The Middle Graptolite Schists (or Dicranograptus Schists). 
To these the author has devoted much labour, and, seconded by 
Herr Schmalensee, of the Swedish Survey, has succeeded in making 
out the entire succession among them. They consist everywhere of 
shaley beds not unlike those of the Phyllograptus Schists, from 
which they are separated by the great Orthoceras Limestone. They 
are rarely or never seen exposed in a continuous section, but with 
the aid of investigation of the natural exposures, and by means of 
excavations at critical points, the author has corrected and supple- 
mented Térnquist’s labours, and is able to render a fair account of the 
1 Geol. Forens. Fordhl. 1875, No. 10. 
. Lower Graptolite Schists. 
. Ceratopyge Limestone. 
. Dictyonema Schists. 
. Olenus Schists. 
. Paradoxides Schists. 
. Sandstones, 
me bo Oo HB Or 
