6 Proceedings of the 



III. Exhibition of a Collection ofLiassic Fossils from Pabba andSkye. 

 By Archibald Geikie, Esq. 



Mr GeiMe laid on the table the fossils he had collected, which he illus- 

 trated with the following remarks : — The Isle of Skye is an object of 

 speeial interest -to the geologist, from its containing in tolerable abun- 

 dance the remains of the liassic formation, — one which occurs in but 

 unfrequent patches throughout the whole extent of Scotland. The 

 lias, as developed in that island, stretches from shore to shore in a band 

 about seven or eight miles in length, by from two to five in breadth. 

 Over the greater part of this extent a dark peaty soil covers the strata, 

 so that they are seldom discernible, save where channelled by some moun- 

 tain torrent. The best exposures are therefore to be found at the extre- 

 mities of the belt. Broadford Bay, on the east, affords a general section 

 of the formation. The beds are there free from the dislocating effects of 

 trap dykes, and dip gently under the waters of the bay at an angle of 5°. 

 The lowest members of the series are found at the village of Lussay, rest- 

 ing unconformably upon the red sandstone of Sleat, They consist of con- 

 cretionary sandstones, and dark compact limestones, some of them charged 

 with organic remains. But the most remarkable of these strata is one, 

 irregularly three feet thick, composed entirely of corals of the family 

 Astreidse, which are bound together by an indurated mud. These organ- 

 isms, of which there are several specimens upon the Society's table, were 

 described several years ago by Mr Miller. They differ in size and abun- 

 dance from any species in the lias of England, where corals are exceed- 

 ingly rare ; and they thus give a peculiar character and interest to the 

 Scottish deposit. Beyond Lussay beds of sandstone and limestone alter- 

 nate along the coast. Some of these abound with the characteristic shells 

 of the period. At Breckish, for instance, where the limestone has been 

 broken up in the course of constructing a road, the Gryphcea incurva 

 might be removed from the beach by ship loads. The same fossil, mingled 

 with ammonites, belemnites, and pectens, is found in most of the strata as 

 far as Corrie Farm, at the northern point of Broadford Bay, where they 

 are buried beneath an extensive overflow of syenite. The upper mem- 

 bers of the series are found forming the flat island of Pabba, about three 

 miles out in the bay. Pabba, though not more than a square mile in ex- 

 tent, forms, with its rich green pasture, a striking contrast to the dark, 

 barren mountains of the surrounding shores. The lias is here repre- 

 sented by a series of dark micaceous shales, dipping northward at the 

 angle usual in this district, 5°. They abound with the organisms of the 

 formation ; indeed, so richly charged are some of the beds as to emit a 

 strong foetid odour when rubbed or broken — a fact likewise noticeable in 

 the lias shales of Eathie. There is now on the table a set of these 

 Pabba fossils. The majority have been already noticed by Murchison, 



