INTRODUCTION. 
Remains of Cephalopoda are found in all strata of Gotland, though in variable number, 
being most plentifully represented in the uppermost strata. In the oldest stratum, which 
consists of shale beds, corresponding to the English Upper Llandovery and Wenlock shale, 
they are pretty common. One of the best localities is near Wisby, where Orthoceras 
cochleatum SCHLOTH. abounds and is one of the most characteristic fossils together with 
two fine species of Phragmoceras. The shale beds at Djupvik in Eksta contaim gigantic 
Orthoceratites as O. annulatum Sow., O. Lindströmi Barr. and others. The shale of Petes- 
vik in Hablingbo also harbours several species, many of them the largest ever found in 
Gotland, as a largesized species of Trochoceras. In the coöval sandstone of the southern- 
most part of the island very few Cephalopoda have been found. 
The next stratum in succession, homotaxical with the Wenlock limestone, in the 
south above the sandstone changed into oolite, is not so rich in Cephalopoda. There 
are mostly mere casts of little value. In the oolite again some rather good specimens 
have been found, belonging to some three or four species. A classical locality is at Öster- 
garn, from where so many rare and fine species have been obtaimed as O. angulatum His., 
O. intermedium Borr, O. Hagenowi Borr, O. imbricatum His. and several others. Quite 
the same species occur farther in the south, in an almost identical limestone, along the 
eastern shores of Grötlingbo and Hamra. Several good specimens of the large Nautilus 
Hisingeri p'ORrRB., the Naut. complanatus of HisINGER, have been found there. 
But the true Cephalopodan stratum is the uppermost limestone, the beds of which 
cover two thirds of the surface of the whole island, being carried away by denudation 
south of Fardhem and again appearing in the hills of Hoburg and along the eastern shore- 
line of the southernmost peninsula. Its age is Upper Ludlow and it is separated from 
the Wenlock beds through a great thickness of so called Crinoidal Limestone, which is 
chiefly composed of the remains of crinoidea and of some broken and worn corals. Im- 
mediately below the beds of the Cephalopodan limestone there are thick banks of the 
large bivalve shell Megalomus gotlandicus and these beds stretch along with the Cephalo- 
poda, sometimes intermingled with them from the northern shores of Gotland at Wialms- 
udd in Fleringe as far south as Ardre and Alskog, thus occupying a zone of seven Swe- 
dish or 42 English miles in length. 
In order to clear up the stratigraphical conditions, in which the Cephalopoda of 
Gotland are found, the annexed table may be of some use, showing the different geo- 
logical links of which Gotland consists, according to the latest researches. 
