W. G. Fearnsides—Lower Ordovician Rocks of Scandinavia. 261 
mutation D. norvegicus, on the other hand, seems to be a comparatively 
late form, and shows nearly all the features of a well-marked 
Dendroid. Ata horizon very near the place of Dictyograptus flabelli- 
formis true graptolites without crossbars appear among the Dictyonemas, 
and as we pass up form an ever-increasing proportion of the graptolitic 
content of the shales. Curiously enough, these true graptolites, which 
may for the present be alluded to as Bryograptus, though intimately 
interlaminated with Dietyonema or Dictyograptus, ave hardly ever 
seen upon the same bedding plane, and it would almost seem as if 
they flourished under slightly different conditions. Dictyonema and 
Dictyograptus, though gregarious, are also to some extent exclusive 
towards each other. 
Above the Dietyonema beds are the calcareous shales and limestones 
with Symphysurus incipiens, 8a a, which, though grouped by Brogger 
with the Ceratopygekalk, would be included in the A beds in Sweden. 
They mark a vast change in the character of the sedimentation, and 
hence the fact that Asaphids are quite as abundant as the Olenids is 
not surprising. The overlying Ceratopygeskiffer 3a, which shows 
a temporary return towards Alum Shale conditions, contains a 
Ceralopyge fauna, but the finding at Gjeitungholmen of a slab from 
this division showing Dictyonema and Bryograptus on the one side and 
Shumardia on the cther convinces me that it is really a passage series 
between A and B. 
In Skane the Dictyograptus beds like the Acerocare zone below are 
lithologically again a part of the Alum Shales. At Sandby (near 
Lund) in the western district the Acerocare zone is subdivided by the 
Swedish geologists (S1 and $6) into (ce) bed with Parabolina heres, 
(6) bed with Parabolina,megalops, (a) bed with Parabolina acanthura 
and A. ecorne, while at Akarpsmolla an additional higher subzone 
(d) with Acerocare = Cyclognathus micropyge is also distinguished. 
In the bed (4) I was able to obtain a few fragments of Megalaspid 
tails, and in certain fine-grained orstens! of (¢) such occurrence is not 
rare. Above this Acerocare zone come the shales and pyritous orstens 
with Dictyonema, not over well preserved, but quite like the Dictyonema 
of the lowest 2e of Kristiania. This bed has the further interest 
that it has yielded to Moberg (S3) Lingula, Acrotreta, Megalaspid 
fragments, and a trilobite Hysterolenus Yornquisti, ‘‘ which is inter- 
mediate between Ceratopyge and Dikellocephalus on the one hand and 
Niobe and Megalaspis on the other.” At Fagelsangsbeck (S 2), a mile 
nearer Lund, the section is continued, with what omission I cannot 
tell. There the lowest bed seen is a black Alum shale with well- 
preserved Clonograptus flexil’s, etc., and fine large Odolella Saltert. 
Some seven feet above this certain much weathered shales show 
laminz crowded with coarse, square-meshed, strongly-barred Dictyonema 
like D. norvegica (and as such identified by Moberg), alternating with 
ill-preserved Bryograptids. Large orstens associated with these shales 
1 The name ‘orsten’ is applied by the Swedes to the highly crystalline bitumen- 
bearing concretions which occur among the Alum Shales. These are the Stinkstein 
or Stinkkalk of the Germans. They have been formed not long subsequently to 
Mee ae of the deposition of the shales, and often contain many beautitully preserved 
ossils. 
