370 Professor Sedgwick and Mr. Murchison on the 



ancient sea penetrated this part of the valley of the Inn during, and long 

 after, the deposition of the coal. 



The general relations of the whole system to the neighbouring secondary 

 rocks, will be best seen by referring to the accompanying section ; which 

 shows that it is basin-shaped, and that it dips from the mountain chains, on 

 both sides of the Inn, towards the centre of the valley. 



The several horizontal galleries by which the coal of Haring has been 

 reached at dilferent levels, exhibit a gradual thickening of all the associated 

 beds as they descend, unconformably, from the sides of the secondary rocks 

 into the valley of the Inn. Thus the coal which had only a thickness of 

 twelve or thirteen feet in the early works, where the mineral rose to the day 

 on the mountain side, was found to have increased to twenty-five feet when 

 the Francisci-Stollen was driven ; and it has a thickness of thirty-four feet 

 where it is now worked at a still lower gallery, the Barbara-Stollen. 



For like reason, the lower adit or Barbara-Stollen offers a more expanded 

 section of the several groups than the Francisci-Stollen, which is 160 feet 

 higher; the former extending 730, and the latter only 550 feet through the 

 same series of beds above the coal : and so greatly do the strata swell out in 

 the prolongation of their dip, that were a gallery to be driven on the level of 

 the Inn, it must extend more than 1200 feet through the same overlying beds 

 in order to reach the coal, which at that depth has been proved by actual 

 boring to be about 50 feet thick. From these data, combined with the average 

 inclination of the beds, it has been calculated that the greatest thickness of 

 this tertiary group, when measured on a line perpendicular to the planes of 

 stratification, is not less than 700 or 800 feet. 



The gradual thickening of the beds from the sides to the centre of the 

 basin, is a strong proof that the deposit was accumulated in an estuary ; for 

 such appears to be the manner in which matter is now deposited at the mouths 

 of rivers which empty themselves upon a steep shore. This analogy is con- 

 firmed by other peculiarities of the Haring formation ; for the beds accommo- 

 date themselves to, and are moulded upon, the declivities of the older forma- 

 tions. Thus we find the overlying strata slightly inclined at their highest 

 level on the mountain side, but their dip increases to 36° (its maximum) at the 

 Barbara-Stollen, which appears to have been the steepest part of the ancient 

 shore ; and below it the inclination of the beds again gradually diminishes 

 with the augmentation of their thickness. 



The structure of some of the subordinate beds further confirms the pro- 

 priety of a comparison of this deposit with modern estuary accumulations : 

 for among several parts of it, which by themselves would be difficult to account 



