b G. LINDSTRÖM, ON TllE SILUKIAN GASTROrOUA AND PTEUOPODA OF GOTLAND. 



followed without interruption all ulorig the coast from Hallshuk, in the nortli, to Gni- 

 svärd, south of Wisby or for ti length of nearly 6 Swedish or 36 Eriglish rniles. At 

 Gnisvärd, Avhere the fossils are already, with regard to several species, identical vvith 

 those found plentifully at Westergarii, the strata are obscured for about an English 

 mile and a half by accuinulations of sand and then again the same shale beds reap- 

 pear horizontal as before and continue with a few breaks to the vicinity of Klinte. 

 It is highly improbable that there should be any traces of superposition of the strata 

 of* Westergarn and Klinte above those of Wisby on the narrow belt covered by the 

 drift. The shale beds of Westergarn whieh have so miich in common with those of 

 Wisby are combined with the shales of Eksta and Habblingbo through the shale beds 

 of vStora Carlsö. As I have shown in a former paper ^) the beds of Westergarn and Stora 

 Carlsö are absolutely identical, having not only a great percentage of species in com- 

 mon, but these species are also of exactly the same varietal habitus. Further, there 

 is no doubt that the shale of Stora Carlsö is in direct continuation with the shale of 

 the nearest, opposite shore of Eksta and that this again is combined with the shale of 

 Habblingbo. We have thus a continuation of shale beds along the coast for a length of 

 nine and a half Swedish miles or 57 English ones. But these beds spread also, as can 

 easily be seen in nuuierous sections, far inland under the limestone beds. The shale of 

 Petesvik in Habblingbo can be traced from the shore upwards for a Swedish mile, to 

 the saw mill of Alfva, having there reached a height of 80 feet. Quite the same sort 

 of shale is again met with in Fardhem, where there are sections in several places 

 and the shale retains nearly the same paheontological character as at Habblingbo. 

 The same form of Rhizophyllum Gotlandicum has been found in both localities. 

 But in Fardhem the shale begins to contain particles of mica and quartz in greater 

 abundance than elsewhere and in fact partially to cbange into something intermediate 

 between shale and sandstone, and this gradual transition can be followed, as it were, 

 step by step along the road leading from Fardhem to Rone where the lowest stratum 

 is found to have been completely changed into sandstone. This predorainates along 

 the shore towards the north for nearly three Engl. miles, now and then changing into 

 patches of shaly limestone and at last passing into shale, as I remarked as long since 

 as 1857^). South of Rone, again, it is connected with the sandstone beds of the southeru- 

 most Gotland. The sandstone beds there and the shale beds of the north of Gotland 

 thus belong to quite the same geological horizon and gradually pass into each other. 

 But, as now the shales of Central Gotland lie under the hills of Klinte, Sandarfve and 

 all other limestone beds there, the limestone hills of Hoburg must be considered as 

 detached outliers of that central limestone plateau, with which they have in common 

 many characteristic fossils, though separated from it by a wide region, where the upper- 

 most beds have disappeared through denudation. A distance of nearly four Swedish 

 miles intervenes between the northernmost hill of Hoburg and the nearest point north- 

 wards near Burs church, where the limestone is again found. Between the lowest stratum 

 of shale and sandstone and the uppermost limestone, commonly called crinoidal limestone, 



^) »Anteckningar om silurlagren på Carlsöarue» i Öfvers. Vet. Akad. Pörhandl. 1882, nr 3, p. 5. 

 2) Öfversigt Vet. Akad. Förhandl. 1857, p. 33. «Till Gotlands Geologi». 



