older Deposits of the North of Germany and Belgium. 293 



the whole mass dipping at a great angle towards the Brocken. At Bucker Berg the iron ore forms an 

 enormous mass, resembling some of the deposits near Dillenburg ; but it still preserves a rude conformity 

 to the prevailing strike and dip of the beds. 



Over the preceding series are dark slates and kiesel schiefer ; and, if we are not misinformed, Posi- 

 donia schist has been discovered on the same line, though in our rapid examination we were not for- 

 tunate enough to find it. Close to the granite the beds are entirely mineralized ; and in most of the 

 geological maps are represented by a distinct colour under the names of Trap, Diorite, Hornfels, <Src. 

 From under the preceding series rises the dark bluish grey coralline limestone of Elbingerode, which in 

 its mineral character, as well as in its fossils, is the perfect counterpart of the great limestone of West- 

 phalia. (See the section, PI. XXIII. fig. 17.) 



Taking then this limestone as a centre, we have an ascending section towards the Brocken, agreeing 

 (not merely in its general relations but even in its mineral accidents) with many of the ascending sec- 

 tions, from the great limestone of Westphalia to the base of the carboniferous system. 



We believe that the great limestone of Elbingerode forms a kind of irregular dome, throwing off' nearly 

 the same succession of beds to the N.W. and to the S.E. It undergoes many changes of colour and 

 structure, especially in the vicinity of the igneous rocks by which it is pierced, when it sometimes becomes 

 very hard and crystalline, and nearly loses all traces of regular stratification. 



We, in the first instance, continued the section to the S.E. along the Bode, by Rubiland and Bohman's 

 Hcihle, and thence down to Schiefer Thai ; and the phsenomena were in the following order. A little 

 below Elbingerode the limestone is cut through by a great band or dyke of porphyry ; beyond which 

 it becomes lighter coloured, obscurely stratified, and more jointed. Again, a large trappean mass inter- 

 rupts the limestone ; some of it passes into a nearly compact feldspathic rock, other parts are dark and 

 almost basaltiform ; but its structure is very variable. This mass may be regarded as the centre of ele- 

 vation ; for beyond it the dip of the limestone is reversed to the south-east. The same dip is continued in 

 a greater succession of beds of subcrystalline limestone, through Rubiland and Bohman's Hohle ; and a 

 little below the latter place a mass of porphyritic trap has broken through the limestone and brought 

 up some beds of the inferior grauwacke*. 



Beyond this spot are some beds of crystalline limestone quarried for marble, not far from which 

 are masses of iron ore. This part of the series is followed by a great succession of stratified trap- 

 pean rocks, some of which are extremely cellular (blatterstein) ; others pass into green and thinly 

 laminated schaalstein ; some resemble earthy regenerated beds, while others are more crystalline, and 

 pass into a true porphyry with a compact base. These singular rocks are continued into a part of 

 Schiefer Thai considerably below the village of Neuburg, and are then replaced by dark glossy slates 

 containing a few calcareous veins. 



Several of these bands of slate alternate with the schaalsteins and other stratified trappean rocks, 

 the whole series preserving the same strike and south-easterly dip. 



To the section just described many of the ascending sections of Westphaha and 

 Nassau, which commence with the great hmestone and rise to the base of the car- 

 boniferous series, present the closest analogies. Respecting the age of the con- 

 torted and altered slates which extend to the granite of the Rosstrappe, we possess 

 no materials for offering any exact opinion ; and it is possible that among them 



* We have endeavoured to convey a correct general notion of this succession in our section (PL XXIII. 

 fig. 17) ; but it is obviously impossible on such a scale to attempt any delineation of the more minute 

 details ; nor indeed was our examination of the country of such a kind as to enable us to give them. 

 VOL. VI. SECOND SERIES. 2 Q 



