GEOLOGICAL FEATURES OF BUTESHIRE. 



61 



Instead of attempting any generalisation of the geology of Bute- 

 shire on my own part, I beg to offer a few extracts from L>r Bryce's 

 "Work on the Geology of Arran and Bute : — 



Island of Bute. — The length of Bute from Garrochhead to But- 

 tock Point is 14| miles, and the average breadth about 3 miles. 

 The total area, including Inchmarnock, is 31,835 acres. Three 

 deep depressions or valleys traverse Bute perpendicular to its longer 

 axis, dividing the island into four portions, and marking the 

 boundaries of distinct geological formations. They terminate on 

 either side in bays or indentations of the land, formed here, as in 

 most other cases, at the points of least resistance, the junctions, 

 namely, of dissimilar strata. Those on the east side are the well- 

 known bays of Karnes, Rothesay, and Kilcattan. The low tracts in 

 question show no rock in situ, but are filled with shingle and alluvial 

 deposits, concealing the junctions, strata of peat, and occasional shell 

 beds. The elevation above the sea-level nowhere exceeds 30 feet; 

 and as this is also very nearly the height of the terrace encircling 

 the island, it appears that when the sea stood at that ancient level, 

 Bute consisted of four islands separated by narrow channels. 



The various strata exhibited in Bute are the terminal portions of 

 those great bands of rock, sedimentary and igneous, which extend 

 across the country from sea to sea; mica slate occupies the northern 

 portion, between the Kyles on the north and Karnes and Ettrick 

 Bays on the south. The rock has its usual character and aspect, 

 and rises into hills of nearly 1000 feet elevation. The district 



