EXPLANATION OF THE PLATES. 



England, and nearly so in France and Germany, but extensively developed 

 within, as well as on the skirts of, the Alpine chain ; as at Gosau in the one case, 

 and at Kressenberg in the other. The term "Gosau Deposits" is adopted to 

 prevent ail ambiguity, and they are shown to be supra-cret?ceous in figures 6, 7, 

 y, and 1^> of the Plate of Sections. For various patches of this formation see the 

 Map. M. Bouc has traced it into the Carpathian chain. The iron ore of the 

 Kressenberg- is placed in this group. 



No. 4. comprehends all the strata from (he scaglia or red chalk of the Southern Tyrol 

 down to the base of the green-sand series, in the lowest term of which the authors 

 place the Vienna grit or sandstone. See particularly figs. 4. and 5. of Plate 

 XXXVI. The iron ore of Sonthofen is in the upper or cretaceous part of this 

 group. 



No. 5. This group, comprehending the Alpine and Jura limestones with dolomite, &c. 

 includes the whole of the oolitic series and lias, and most of the salt-breccias or 

 rock salt, as well as the principal lead veins of the Alps. 



No. 6. The ferruginous red colour represents a group supposed to be of the same age 

 with the new red sandstone and magnesian limestone. Salt and gypsum occur in 

 it, though not in such abundance as in the limestone No. 3. 



No. 7. The term " old slaty rocks" is here applied in a very comprehensive sense, 

 and embraces every formation from the primary crystalline rocks, up to those of 

 true transition type, occasionally containing organic remains. 



(Spathose iron ore is most abundant in this class of rocks, though it does sometimes 

 occur in granitoid rocks, and also in primary limestone.) 



No. 8. represents the granitic axis of the chain, the general direction of which bears 

 from W.S.W. to E.N.E. A remarkable bifurcation takes place near its eastern 

 extremity, the southern branch of which stretching out into the Pach and Kor 

 Alps, and thence into the Bacher-Gebirge, encircles the tertiary basin of Lower 

 Styria; whilst the northern branch or continuation of the principal chain separates 

 the Styrian basin from that of Vienna. It reappears in the Leitha Gebirge, and 

 again beyond the Danube in the Carpathians. 



The intrusive or igneous rocks are designated under two colours only, it having been 

 found impracticable in a map of this scale to make a further separation of the 

 different rocks of volcanic origin. 



a. All volcanic rocks which traverse the tertiary or secondary deposits. 



b. Older porphyries (as in the Southern Tyrol) which were consolidated anterior to 



the formation of the new red sandstone. 



Plate XXXVI. 



Sections. 



This Plate contains sixteen transverse sections illustrative of the structure of the 

 secondary and tertiary formations of the Eastern Alps. Fig. 1. is an ideal sec- 

 tion, and is prefixed to convey a general notion of the structure of the chain, and 

 of the relations of the above-mentioned deposits to an axis of primary and transi- 



