328 



confounded with the lias grits, from which they are clearly distin- 

 guished both by fossils and superposition. 



A very detailed section is then given of all the strata exposed 

 in the gorge, called the Porta Westphalica, by which the Weser 

 escapes into the plains of Minden, and where all the sub-formations 

 of the oolitic series, consisting of shales, grits, bands of oolite, &c. are 

 well exposed. The beds are here considerably inclined, and include 

 representatives of the English series, from the top of the lias to 

 shales of the age of the Oxford clay. All this system of the inferior and 

 middle oolite, passes, it is observed, beneath the Biickeburg range of 

 hills, containing sandstone and calcareous shale with workable seams 

 of coal, which group the author agrees with M. Hoffmann in refer- 

 ring to the upper system of the oolitic series, and states that it con- 

 tains many marine shells ; whilst he distinctly shows that it is not 

 the green-sand, of which there are clear sections in the immediate 

 neighbourhood. 



Middle Oolite. — Jura Kallc, 8sc. — The mineralogical characters of 

 the middle oolite of central and southern Germany are pointed out as 

 being essentially different from those of rocks of the same age in 

 Westphalia and Hanover : so that instead of the shales, grits, &c. just 

 described, they consist in one part of compact, cream-coloured lime- 

 stone, and in another of dolomite. In Franconia (the great region of 

 bears' caves), in the hills opposite Banz, and in many other places, the 

 dolomite usually caps the limestone, the latter containing the greater 

 number of the fossils. In these groups, and in the inferior oolite, 

 Count Miinster has detected nearly all the species of Ammonites 

 figured from this part of the series in the Mineral Conchology, with 

 many other new species ; and has also procured at least sixty species 

 of Scyphia from the middle Jura kalk, and many other zoophytes now 

 figured in Goldfiiss. 



Solenhofen Slate. — The Jura limestone or middle oolite is observed 

 within a certain limited district, between Kehlheim on the S.E. and 

 Pappenheim on the N.W., to pass upwards into a slaty, compact 

 limestone, which is exposed in plateaux overlying dolomitic Jura 

 kalk on both banks of the river Altmiihl, but is of sufficiently 

 fine texture, in only a few quarries near Solenhofen, to be worked as 

 lithographic stone*. The quarries are then described, and their 

 fossil contents, as collected by the author or observed by him in the 

 collections of Count Miinster and others, are enumerated. Seeing 

 the prevalence of Pterodactyli, Insects, Crustaceae, and Tellinites, 

 and knowing that these fossils, together with certain plants, are 

 also found in the Stonesfield slate of England, and further that these 

 slaty beds at Solenhofen immediately surmount limestones, which 

 by their contents are found to be the equivalents of the middle and in- 

 ferior oolites of England, on which the Stonesfield slate also rests, — 

 he is led to consider it probable that the Solenhofen and Stonesfield 

 slates are of a similar age; an opinion which he believes has been re- 

 cently expressed by Dr. Boue. 



* For a specific account of this range, see Von Buch's Letter to Brong- 

 niart, 1823. 



