D. Mackintosh — The Drifts of the Lake District. 303 



count. Its bottom is a very gradually sloping one, tolerably deep at 

 ■ the western end or opening of the bay, and shallow at the eastern 

 extremity. Now the eastern portion is the only one which we need 

 consider, as it is within it that the site of Is is said, according to 

 every version, to be. In this space then, the deepest sounding that I 

 have been able to find is between seven and eight fathoms, so that 

 an elevation to that extent would convert the whole of the eastern 

 end of the bay into dry land. Now all the facts which we have 

 detailed above, tend to show that the depression of the land is still 

 at work, and assuming that it has continued ever since (how long 

 before we need not inquire) the traditional date of the submergence 

 of Is, we get an average rate of depression of three feet per century 

 — by no means an extravagant allowance. The effect of the eleva- 

 tion of the land some forty-five feet would, it will be seen by 

 referring to the accompanying sketch-map, not disturb the geo- 

 graphical descriptions of the district given by Ceesar and others. I 

 wish it to be understood that I am in no wise arguing that the 

 depression in question was anything more than a local one ; as I am 

 aware that it is held that the Northern, Southern, and South- 

 western coasts of Fi-ance are within the European area of elevation. 

 That such a local sinking of the land exists in Basse Bretagne, I 

 think I have shown sufficiently ; and my object will be served if I 

 have also shown that, at the time that Is is said to have been the 

 pride of King Gradlon's kingdom, there is every probability that 

 land did exist at the very spot with which that semi-mythical city 

 has always been associated. That such a probability greatly enhances 

 the value of the tradition, and of the otherwise slender evidence 

 which supports it, is ob^^ous. I have thus done my best as a geologist 

 to bring back an old legend within the realms of truth, and I must 

 now leave it to the antiquary to find out more concerning lost and 

 forgotten Is. 



IV. — On the Dkifts of the West and South Bobbers of the Lake 

 District, and on the Three Great Granitic Dispersions. 



By D. Mackintosh, F.G.S. 



{Continued from our last number, p. 256.) 



Boulder- scars. — From Maryport to Parkgate, the E. coast of the 

 Irish Sea at intervals exhibits accumulations or concentrations of 

 large boulders, which are locally called scars. They may be seen in 

 all stages of formation, from the denudational area, where they are in 

 course of being left by the washing away of the clayey matrix, to 

 the depositional area, where they have become half-covered with 

 recent sand and shingle. In many places (as between Seascale and 

 near Silecroft) there are so many boulders within a small area as to 

 show that a considerable thickness of the clay must have been re- 

 moved. With the exception of having tumbled down as the clifis 

 were undermined and worn back by the sea, many of the boulders 

 may still rest nearly in the positions they occupied in the clay, but 



