4 THORELL & LINDSTRÖM, SILURIAN SCORPION FROM GOTLAND. 



beds at Wisby, with Pterygotus, Ceratiocaris, and the Scorpion, are 120 feet above 

 the sea. 



Before giving an account of the discovery of the Scorpion, it may be as well 

 first to mention the other fossils which have been found in the same beds with it, and 

 then to try to fix their geological position. 



The locality had long been known as rich in remains of marine animals. The 

 inarly limestone and the clay are filled with a great nuinber of minute, giossy, black 

 hooks, which were regarded as the jaws of PolychaBte Annelids by the eminent Swedish 

 palajontologist, the late Professor Angelin, an opinion, which has later been confirmed 

 through the important researches of Hinde and Ehlers. Dr Hinde described^) the 

 jaws of förty species and varieties from this stratum. In addition to these the fol- 

 lowing fossils have also been found in the same spöt. 



Pterygotus osiliensis Fr. Schmidt. Numerous fragments of this remarkable spe- 

 cies are scattered throughout this stratum and show clear evidence of its entire simi- 

 larity to the specimens from Oesel, which have been so well described and beautifully 

 delineated in the -work of Schmidt. It may here be remarked that the species is found 

 in Oesel, in beds, which, accoi^ding to Schmidt, belong to the most recent division of 

 the Silurian of that island. Ceratiocaris sp. tail spines in good preservation, probably 

 the same species as that which at Hammars in Kräklingbo occurs with Eurypterus. En- 

 crinurus punctatus Emmr. sparingly. Phacops Musheni Salter; Phac. Downingice Mxjrcb..; 

 Calymene Blumenbachi Brongn. ; Lichas ornatus Ängel.; Phaetonides Stokesi Murch. is pretty 

 common in the marl or clay, as well as in the limestone below, in complete expanded 

 specimens. Forhesia sp. with large, coarsely granulated glabella; Forhesia sp. with 

 short glabella. Leperditia a small species, very common. Entomis sp.; Cytheropsis sp.; 

 Conidaria asi^ersa Lndm. only found in these beds, Con. Icevis Lndm. ; Discma sp.; Spirifer 

 plicatellus L. var.; MeristeUa Iceviuscula Sow. ; Strophomena, no less than four new spe- 

 cies, Avith thin valves, finely striated, showing affinity to several species described by 

 James Hall from the Lower Helderberg beds of N. America, Eatonia sp. nearly re- 

 lated to the American E. peculiaris Hall from the Lower Helderberg group and the 

 Oriskany sandstone. Crinoidea, two species with well preserved calices and arms, pro- 

 bably belonging to the genera Periechocrinus and Actinocrinus. Thecia Swinderenana 

 Edw. & H., and Acerimlaria luxurians Eichw. 



The evidence afforded by such forms as Pterygotus, the Strophomenidaa and 

 Eatonia, conclusively shoAvs that these Gotland beds at the base of the upperraost lime- 

 stone near Wisby, are the equivalents of the Upper Ludlow strata of England and 

 Scotland; of the Lower Helderberg group of the United States; and of the beds of 

 Kaugatoma and Rootzikiill in Oesel; which are all near to, or at the summit of the 

 Silurian series. Of the sixteen species of Pterygotus enumerated by Dr Henry Wood- 

 WARD, in his Catalogue of British fossil Crustacea, as many as ten have been found in 

 the Ludlow beds of England; and Pterygotus bilobus has been found by Mr Slimon 

 and Dr Hunter in Scotland, in the uppermost limestone beds of Lesmahagow. The 



') On Annelid Eemains from the Silurian strata of the isle of Gothmd, in »Bihang till K. Svenska Veten- 

 skaps-Akademiens Handlingar» Band VII for 1883. 



