102 THE CRUISE OF THE BETSEY ; OR, 



different form, and the glittering mica built up its multitu- 

 dinous layers between. Here the unctuous chlorite con- 

 structed its soft felt ; there the micaceous schist arranged 

 its undulating layers ; yonder the dull clay hardened amid 

 the intense heat, but, when all else was changing, retained 

 its structure unchanged. Surely a curious chemistry, and 

 conducted on an enormous scale ! 



It had been an essential part of my plan to explore the 

 splendid section of the Lower Oolite furnished by the line of 

 sea-cliffs that, to the north of Portree, rise full seven hundred 

 feet over the beach ; and on the morning of "Wednesday I 

 set out with this intention from Isle Ornsay, to join the mail 

 gig at Broadford, and pass on to Portree, a journey of rather 

 more than thirty miles. I soon passed over the gneiss, and 

 entered on a wide deposit, extending from side to side of the 

 island, of what is generally laid down in our geological maps 

 as Old Red Sandstone, but which, in most of its beds, quite 

 as much resembles a quartz rock, and which, unlike any Old 

 Red proper I have ever seen, passes, by insensible gradations, 

 into the gneiss.* Wherever it has been laid bare in flat 

 tables among the heath, we find it bearing those mysterious 

 scratches on a polished surface which we so commonly find 

 associated on the main land with the boulder clay ; but here, 

 as in the Hebrides generally, the boulder clay is wanting. 

 To the tract of Red Sandstone there succeeds a tract of Lias, 

 which, also extending across the island, forms by far the most 

 largely-developed deposit of this formation in Scotland. It 

 occupies a flat dingy valley, about six miles in length, and 

 that varies from two to four miles in breadth. The dreary 

 interior is covered with mosses, and studded with inky pools, 



* Professor Nicol of Aberdeen believes the Red Sandstones of the "West 

 Highlands are of Devonian age, and the quartzite and limestone of Lower 

 Carboniferous. See Quarterly Journal of the Geological Society, February 

 1857. -W.S. 



