6 G. LINDSTliOM, ON THE SILURIAN GASTKOl'UDA AND I'TKUOPODA OF GOTLAND. 



followed without interruption all along the coast from Hallshuk, in the north, to Gni- 

 svard, south of Wisby or for a length of nearly 6 Swedish or 36 English miles. At 

 GnisvJird, where the fossils are already, with regard to several species, identical with 

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

 mile and a half by accumulations 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 which have so much in common with those of 

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

 of Stora Carlso. As I have shown in a former paper') the beds of Westei'garn and Stora 

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

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

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

 the nearest, opposite shore of Eksta and tliat 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 numerous sections, far inland undei' the limestone beds. The shale of 

 Petesvik in Habblingbo can be ti'aced from the shore upwards for a Swedish mile, to 

 the saw mill of Alfva, having there reached a height of 8U 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 pakeontological character as at Habblingbo. 

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

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

 abundiince than elsewhere and in (act partially to change 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 predominates 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 southern- 

 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 lloburg must be considered as 

 detached outliers of that central limestone plateau, with which they liave 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, lietween the lowest stratum 

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



') ».\nteckiiingar oiu siliirlai;i(;ii pii Cailsoariic" i Ofvers. Vot. Akad. Forhaiiill. 1882, nr 3, p. 5. 

 -) Ofversigt Vet. Akad. Foiliaiull. 1857, p. 33. »Till Gollauils Geologi". 



