Proceedings of Societies. 367 



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 

 Astreidss, 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 Gryphaia 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 Sienite. The upper members 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 extent, forms, 

 with its rich green pasture, a striking contrast to the dark, barren moun- 

 tains of the surrounding shores. The Lias is here represented 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, and figured by Sow- 

 erby; but there are several which appear to be new. The most abundant 

 organisms are the Pectens, of which there are at least three species. 

 Other fossils are the Pentacrinites, Plagiostoma, and Terebratula, of 

 each of which there are several species — Gryphcea incurva, and G. Mac- 

 cullochi ; Pinna, probably of several species ; Belemnites, Ammonites, 

 at least four species; Serpulai, &c. The state of keeping of the fossils 

 varies considerably in the different beds. The ammonites exist, in some 

 cases, as mere flattened impressions. Generally they present only the 

 outer ring, the central portion of the disc having entirely disappeared. 

 In not a few of the layers the condition of the organic remains seems to 

 indicate protracted maceration — a conclusion rendered probable by the 

 abundance of casts of the more tender species. The western coast of Skye, 

 along the shores of Loch Slapin, presents a rich field of study to the geo- 

 logist. The Lias, for the space of several miles, is traversed in all direc- 

 tions by dykes and veins of basalt. In some places the limestone is 

 black ; in others, of different shades of gray ; while inland, towards Kil- 

 cbrist, it takes a snowy white ; but in all cases it has been altered into a 

 compact marble. A series of specimens upon the table exhibits the pas- 

 sage of a calcareous shale, abounding with Gryphsea and Pecten, into a 

 hard fossiliferous limestone, which in turn shades off' through various 

 hues of black and grey into a white crystalline marble, destitute of or- 

 ganic remains. The latter rock, as it lies in the quarries at Kilchrist. is 

 not much inferior in colour to the best stone of Italy, though, after being 

 cut and exposed for a few years to the air, it acquires a dirty yellowish 

 tinge. The trap dykes are themselves a curious subject for investigation. 

 Owing to the decomposition of the marble around them, some of large 

 size are seen running up the hill sides like walls. Indeed, when two or 

 three cross each other, the appearance presented reminds one of some 

 ruined relic of the feudal times. Others may be found insinuating them- 

 selves among the cross rents of the contorted strata, and terminating in 

 a point as fine as that of a pen. The shores of Loch Slapin are, on the 



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