120 . REPORT — 1859. 



the eastern extremity of the section, the quartzite was Drought into contact with 

 the gneiss along a nearly vertical line of fault, but without dipping under it, and 

 the same relation was shown in another section from the Loch Carron district. 



These sections, to which many others might be added, abundantly prove that there 

 is here no continuous, conformable, upward succession, but that this portion of the 

 Highlands is made up of a series of fragments of strata brought side by side by 

 enormous slips and powerful lateral pressure. This lateral compression was shown 

 in the contorted lamination of hand specimens of the rocks from the two sides of 

 the faidt. This pressure may in some cases have caused an apparent overlap of the 

 lower beds on the higher, though in the whole line of junction, 100 miles in extent, 

 Prof. Nicol has never observed any clear case of this nature. But that such cases 

 could only be mere accidents is proved by many facts. The superposition of the 

 red sandstone to the gneiss can be observed over miles and miles of country ; that 

 of the quartzite to the red sandstone is no less distinct, being readily traced by 

 the eye from mountain top to mountain top, from valley to valley ; and again the 

 limestone, though a small formation, everywhere clearly reposes on the quartzite — 

 at Durness, Emboli, Loch More, Assynt, Ullapool, Loch Maree, Loch Keeshorn. 

 But how is it with the next step in the supposed series ? Nowhere is an overlap of 

 more than a few feet or yards even said to be seen, though the supposed overlying 

 rocks extend more than thirty miles to the east, the underlying fully as much to 

 the west. The fact, too, that the eastern gneiss is brought into contact in one place 

 with the limestone, in another with the quartzite, in a third with the red sandstone, 

 according to the amount of denudation, and all within a few miles, prove that the 

 junction is along a line of fault, and is wholly inexplicable on the supposition of 

 conformable upward succession. 



The mineral character of the eastern gneiss has also been referred to, as proving 

 it a newer rock. But this is founded on the unproved assumption that the coarse- 

 grained gneiss is older than the fine-grained, whereas the reverse is neai'er the truth. 

 Prof. Nicol stated that he had formerly shown that in the Southern Grampians the 

 clay-slate and mica-slate were probably older than the gneiss, and he believed that 

 the same relations existed in this north-west part of Scotland. Where the greatest 

 upthrow of the eastern gneiss has taken place, we have clay-slate brought into 

 contact with the quartzite, and covered successively by mica-slate and true granitic 

 gneiss. Where the upthrow is less, only the mica-slate and gneiss are seen, or even 

 the gneiss alone in contact with the quartzite. He therefore affirmed that we 

 have in this north-west region of Scotland a line of fracture analogous to that 

 along the southern flank of the Grampians, and not inferior to it in extent and 

 influence on the physical structure of the country. 



On some neiv Boreal forms — the nearly perfect skeletons of Surf and Eider 

 Ducks, Oidema and Somateria — accompanying the remains of Seals, from 

 the Pleistocene Brick-clays of Strathcden, Fifeshire ; nine miles inland, 

 and 150 feet above medium tide-level. By D. Page, F.G.S. 



On the Structure, Affinities, and Geological Range of the Crustacean Family 

 Eurypterida, as embracing the genera Eurypterus, Pterygotus, Stylonurus, 

 Eidothea, and other doubtful Eurypteriles from the Silurian, Devonian, 

 and Carboniferous strata of Britain, Russia, and North America. By 

 D. Page, F.G.S. 



On Fossil Fish, new to the Old Bed Sandstone of Caithness. 

 By C. W. Peach. 



The first mentioned was a small but very beautiful Acanthodus from the quarry 

 of the Earl of Caithness near Barrogill. He turned it up about four years ago. The 

 species is not yet decided. It is, however, a curious fact that the same genus should 

 have been met with in Forfarshire and Caithness about the same time ; .and another 

 from Thurso, much smaller, with strong and long spines, and as if clothed with a thick 

 skin. This and the three next are not named. The great interest attaching to the next 



