W. G. Fearnsides—Lower Ordovician Rocks of Scandinavia. 268 
zone within these provinces, but a thin bed of rather barren shale 
just below the Dictyonema zone may well represent it. The Dictyo- 
nema zone itself also is rarely seen, but its absence is probably due 
rather to subsequent erosion than to failure of deposition. In Vester- 
gdtland Dictyonema shale is recorded by Linnarsson (W 1) at certain 
places around Halleberg and Hunneberg, but most unfortunately I was 
not able there to findit. At Kelfva, west of Mosseberg (W 4), and at 
Orreholmen, near Gerumsberg (W 5), in the Falbygden district, 
however, its lower members are preserved beneath the Ceratopygekalk. 
At Kleva the highest beds seen contain the largest and widest meshed 
Dictyograptus I have ever seen. An orsten among the shales con- 
taining this is described by Von Post! as including a bedding plane 
with abundant glauconite, but this I did not notice. 
In the Berg or Vreta Kloster district of Ostergétland (1) there 
are several fine exposures, and at Storberg not less than 18 feet of 
Dictyonema-bearing shales are seen. Here the Acerocare beds seem 
to be actually missing, and a bed of calcareous or cherty sandstone 
with fragments of thick-walled Obolus and up to a foot in thickness 
separates the Dictyonema beds from Peltura-bearing orstens.*? The 
Dictyonema beds seem fairly complete, and the highest beds contain 
stipes of true graptolites along with Dictyonema. These beds are 
worked along with the underlying Olenus shales, and contain sufficient 
bitumen to be quite useful for fuel. 
In Nerike the Dictyonema beds, shales, and associated sandstones 
appear to be absent. 
From the drift of Gefle and Upsala, Wiman (B 1) has obtained many 
blocks of Odolus-bearing sandstone comparable with the Obolus con- 
glomerate of Oland. Here, however, it is truly conglomeratic, contains 
much glauconite and some phosphate nodules, and has a limestone 
matrix. With it are associated boulders of certain shales containing 
stipes of graptolites, Shumardia, and also Hysterolenus Tornquisti (B 2). 
In the Lake Siljan district of Dalarne the Odolus sandstone described 
by Tornquist (D1) from Vicarby and. Klitterberget may probably be 
referred here. It is now well seen in the railway cutting half-way 
between Rettvig and Vicarby. There it has a thickness of from 
38-7 feet, and consists of fresh chips of quartz felspar and mica 
with angular granite pebbles and a kaolin matrix. Its cement is 
calcareous, and it rests upon an irregular surface of granite, which 
shows contemporaneous weathering, affecting different grades of rock 
so differently that the depth of weathered rock varies from two inches 
where the rock is aplitic to as many yards in the coarse-grained 
granite. Of fossils Obolus Apollinis occurs in great multitudes, but 
other species are indeterminate. 
A Subaqueous Unconformity.—At the close of the Dictyonema shale 
period sedimentation over the eastern portion of Scandinavia must 
have become discontinuous, and in certain places may at times have 
been replaced by erosion. Of actual uplift with its attendant 
1 G.F.F.S., November, 1906. : 
* Wiman (E2) at Vestana describes a similar sandstone bed 2:08 m. in thickness 
interlaminated with Dictyonema-bearing shales. 
