XVIII 
ERIK A : SON STENSIO 
which they are in the field bounded in a strikingly sharp manner. The vertical height 
from the Hustedia limestone to the upper boundary of the fish horizon at the locality 
in question is, according to barometric measurements, about 90 m. It was not possible 
to find any bone-bed corresponding to the one discovered by Salomon in 1910 (Stolley 
19nl not far from this place. The fish horizon, which seems to coincide with the 
Posidonomya shales, probably has an approximate thickness of about 15 m or more. 
The series of strata between the Hustedia limestone and the fish horizon seems to 
show a development that is similar on the whole in all the Ice Fjord region to that 
just described in Dickson Land. Detached blocks from a bone-bed with Triassic fishes 
were found by Dr. E.Wiren and Pharm. Cand. A. Stensio during the summer of 1920 on the 
east side of Mt Ber- 
til and the character 
of the blocks shows 
that the bone-bed 
must have been situa¬ 
ted somewhat beneath 
the fish horizon in the 
bright sandstones. 
The fish horizon is 
very "well characteri¬ 
zed by its abundant 
fauna of both ever- 
tebrates and verte¬ 
brates. It seems to be 
thickest and most rich 
in fossils in the moun¬ 
tains of the Sassen 
Valley district. It is 
thinnest and least rich 
in fossils atMt Bertil. 
It also contains very 
sparsely with fossils 
and is probably rather unimportant at Mt Hogskolan and the most northerly parts of 
the field at Dickson Land. It is on the whole rather sandy, as on the west side of 
Dickson Land, but in spots, as on the south side of Sassen Bay, it may have a more 
purely shaly character. Sometimes, as on the east side of Mt Marmier, a couple of rather 
thin bone-beds are found in it. 
Its upper boundary is everywhere sharply marked by a black shaly cliff, which 
is also very well seen in the togography (see text figs, b, c, in which the upper boundary 
of the fish horizon is marked). 
Like the underlying sandstones the fish horizon is seldom exposed or accessible 
in a firm cleft. It is therefore only possible as a rule to collect loose weathered con¬ 
cretions, split off by frost and mostly scattered about after sliding down the rather 
steep slopes. The finds are consequently almost always fragmentary. The appearance 
Text fig. b. Part of Mt Bertil from Ekman Bay. Photo A. StensiS, 1920. 
Upper Carboniferous in the steep shore. Then a slope, covered with vegetation and consisting 
of Permo-Carboniferous strata, after which comes the so-called Permian-and the lower Triassic 
(the lightest part forming the base of the real mountain-cliff). The lowest line denotes the' upper 
boundary of the.fish horizon. The other two the approximate position of the lower and upper 
Saurian horizon respectively. N. B. shaly bed above the fish horizon. • 
