26 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Juiie 3, 



and 2ndly, that the sandstone of South Gothland underlying such 

 limestone, was necessarily the oldest rock in the island. When how- 

 ever the limestones of North and South Gothland are clostly com- 

 pared, the essential distinctions both in fossils and superposition 

 above-described, fortify me in the belief, that Hoburg is unques- 

 tionably of younger age than the north-western and central masses 

 of the island. 



In every section in the northern part of the island, whether on 

 the coast or in the interior, the great limestone, as already explained, 

 rests on shale charged with Wenlock shale fossils, whilst the lime- 

 stone of Hoburg stands at once upon pisolite, oolite and sandstone, 

 containing a group of Ludlow rock fossils which have nowhere 

 been found beneath the Wenlock limestone. Thus stratigraphical, 

 lithological and zoological evidences combine to support my view. 

 Again, if the sandstone and oolite were so low in the series as 

 Hisinger and Helmersen suppose, why should we have no traces of 

 such rocks and fossils in that part of the series in other parts of 

 Scandinavia ? 



At Kinnekulle and all other places, whether in Sweden or in 

 Norway, where an ascending series can be continuously observed, 

 the Lower Silurian limestones, wherever I have seen them, are covered 

 by great thicknesses of Graptolite shale ; but nowhere is there a trace 

 in thathorizon of oolites and peculiar calc grits and sandstones similar, 

 either in lithological or zoological aspect, to those of the south of 

 Gothland. The truth then seems to be, that this being the only 

 tract in the Swedish kingdom where an ascending series is traceable 

 so far upwards as to pass gradually from rocks loaded with Wenlock 

 fossils into others in which Ludlow forms predominate, we might 

 reasonably look for a peculiar fades of the rocks. An oolitic 

 structure having long been known in some of the carboniferous 

 limestones of England*, and having since been shown to exist in the 

 Devonian rocks of Russia, we now simply extend the demonstration 

 downwards, and indicate that similar arrangements of calcareous 

 particles took place in the Upper Silurian strata as in succeeding 

 periods ; the fact is however interesting as indicating the most 

 ancient oolites hitherto known, and may eventually be of value in 

 leading to the establishment of just theories respecting the origin of 

 certain inorganic phaenomena. 



Should the preceding view of the succession in Gothland be sus- 

 tained, it would appear that in the northern and central parts of the 

 island, where the limestone and shale have the same characters and 

 the same relations to each other as in the typical districts of the 

 Wenlock limestone of England, a striking' identity or similarity of 

 fossils is coexistent in the two countries ; whilst in the southern ex- 

 tremity, where the higher strata assume in part a different lithological 

 structure and are terminated upwards by much purer calcareous 

 masses than at Ludlow, we are presented both with some remarkable 

 species hitherto only found in that formation in England, and with 



* See ' Silurian System/ p. 120, for a description of the oolite of the Clee Hills. 



