6 G. LINDSTRÖM, THE ASCOCERATIDAE AND THE LITUITIDEA. 
limestone, in which there also reigns a great variability, patches or pockets of marl and 
shale occurring in the midst of the limestone and the limestone itself also changes from 
whitish gray to intensely red. The red limestone, so much resembling some varieties of 
the German Devonian limestone of the Harz mountains or even of the Lower Silurian 
Orthoceratite Limestone of the main land of Sweden, predominates in the south of Got- 
land, in the parishes of Lye and Ardre, near Ljugarn, but it is also found on Sandarfve 
kulle. The Cephalopodan limestone is in some places coarse and crystalline, in others 
again soft and earthy. 
The oldest descriptions of Gotland Cephalopoda extant are given by German au- 
thors. The fragments of Silurian rocks which lie scattered on the plains of Northern 
Germany, whether derived from the present Islands of Gotland and Ösel, or probably also 
in large numbers from destroyed strata of lands formerly lying between those islands, 
were the source, from which the German naturalists carly had collected their material for 
description. As usual in these times there were given no detailed descriptions of these shells 
which were called Alveoli, Lapides cancris, from an imagined similarity with the tail of 
the crayfish, also Gammarolithus, Ichthyospondyli sive vertebre piscium, Spondylolithi sive 
Dolicholithi ete. Such general descriptions of nuclei etc., impossible to discern specifically, 
are met with in the works of VOLKMANN, HELWING, REINHARD, KUNDMANN and even SCHRÖ- 
TER and ÅRENSWALD. 
KLEIN was in 1731 the first, who gave any somewhat intelligible descriptions and 
figures in his »Descriptiones tubulorum marinorum. In quorum censum relati Lapides 
caude caneri GESNERI et his similes,. At page 8, under the heading »Tubuli concamerati: 
2 cylindriformes» stands 
»1.  Gothlandicus; crassus; cameris strictioribus singularis, truncatus etc. Tab. 
HH, fig. 3—4.» This is O. cochleatum SCcHLOTH. 
Page 10 we have »Sp. II Superficie aspera. «) sulcati. 
1. Major; Gothlandicus, superficie bis novies sulcata. Siphone inter centrum et 
peripheriam. Tab. V f. 8. Cameras exhibitas in alio Exemplo polito. 
TAHITI TOO 
2. Minor ex viginti sulcis asper. Tab. V fig. 9.> — Both these are O. angu- 
latum WALENB. 
BREYNIUS, JOANN. PHIL. wrote »Dissertatio physica de Polythalamiis. Gedani 1732». 
Page 34 »0O. siphunculo axem transeunte graciliori, Tab. V f. 7» is no doubt an Upper 
Silurian species with closely set septa, but it is impossible to determine it. Boa 
siphone inter centrum et peripheriam externe sulcatus. Tab. VI f. 3—5> is O. angulatum 
WauL. P. 37 »O. siphone ad peripheriam locato, Tab. VI f. 1—2» is O. cochleatum. 
AD. MopÉer is the first Swedish naturalist who gave specific distinctions of our 
species in his paper »Slägtet Rörkamring, Orthocera» in »Sv. Vetensk. Akademiens Handl. 
1796» p. 63—97, 143—170. He unites the Cephalopoda and the Foraminifera in the same 
group, as so many before and after him. Atp. 83 he has »N:o 4, Får-Rörkamring (Orthoc. 
sulcata) Gotland» which no doubt is the often occurring O. angulatum. P. 150. »O adunca 
