1873.] JXTDD THE SECONDARY ROCKS OP SCOTLAND. 187 



and are overlain by deposits, often of great thickness and sometimes 

 much altered, of white chalk and flints. It seems reasonable there- 

 fore to conclude that a like succession of beds prevailed also in this 

 eastern area of Scotland. The general characters, however, of the 

 Cretaceous rocks of Scotland will be described in the Second Part 

 of this Memoir. 



IV. Phenomena presented by the " Brecciated Beds." 



In the previous pages we have described what may be considered 

 the normal aspect presented by the Upper Oolite rocks of Suther- 

 land ; this is best illustrated by the sections on the shore in the 

 neighbourhood of Kintradwell and Lothbeg. As we proceed north- 

 ward from these places, however, we find the same strata assuming 

 new and very remarkable characters, which have deservedly attracted 

 much attention and excited great interest among geologists. 1 allude 

 to the phenomenon first described by Sir Roderick Murchison under 

 the name of the " Brecciated beds of the Ord." 



Prom Garty northward into Caithness the grits and limestones 

 already described as belonging to the Upper Oolites, while in other 

 respects maintaining their normal characteristics, lithological and 

 palaeontological, are found, in certain of their beds, to include nume- 

 rous masses of foreign rocks of various sizes. The frequency of these 

 included blocks appears to increase as we go northward, till in the 

 exposures about the Ord we find the Upper Oolite strata almost 

 wholly made up of fragments of foreign rocks, some of these being 

 of enormous size, crowded together in the greatest confusion, and 

 cemented by a sandy or calcareous matrix. 



The features presented by these remarkable rocks are of the most 

 extraordinary character ; and the peculiarity of their appearance is 

 greatly heightened by the strangely disturbed and contorted position 

 of their strata, which has already been described. From Garty 

 northward to beyond the Green-Table Point we find reefs composed 

 of these " brecciated beds," which consist of materials that resist 

 denuding influences in a greater degree, perhaps, than any other of 

 the Secondary rocks ; and they are formed by the outcrop of beds 

 which exhibit within short distances the most wonderful variations 

 in dip and strike. Thus the appearance presented at low water is 

 that of a number of massive but ruined walls, composed of irregular 

 blocks of stone, often of enormous size ; these vast walls sometimes 

 maintain a perpendicular position, but oftener appear as if slipping 

 from their foundations and inclined in different directions and at 

 various angles ; they strike in turn to every point of the compass, 

 and often form curves, sometimes long and sweeping, indicative of 

 the great folds of the beds of which they form the outcrop, and some- 

 times short, sharp, and repeated, marking the violent contortion of 

 those same beds. Occasionally the appearance of bedding is alto- 

 gether lost, and the shore appears to be made up of a perfect chaos 

 of blocks of stone of the most various proportions and of every con- 



