186 Iicports and Proceedings — 



occurs in la3'ers along the bedding-planes, but frequent! y rises tbrongli 

 the whole thickness of one bed and extends up into the overlying 

 layers. It does not seem likely that it was the root of a Siphonia or 

 some similar organism. Another body which has been also called 

 Spongia parndoxica consists of masses of more crystalline texture, 

 exhibiting upon weathered surfaces a network of small ridges 

 inclosing cup-like depressions. These appearances were compared 

 by the author to the weathered surfaces often seen in certain beds of 

 the Mountain Limestone and in gypsum; the masses show no traces 

 of internal structure. 



The author stated that sections of these bodies show exactly the 

 same characters as the containing rock, except that the material is 

 more compactly crystalline ; it contains the same fragments of shell, 

 etc., and the same sand and pebbles. He regarded them as of con- 

 cretionary origin, and explained their symmetry of form and regularity 

 of arrangement by their being formed at the intersections of joints 

 with the bedding-planes or with one another. Phosphatic nodules 

 occur in the lower parts of the White Chalk, and had these bodies 

 been sponges, they would probably have been phosphatized ; but 

 analyses have shown no marked diiference in this respect between 

 their substance and that of the surrounding rock. 



3. " Further Notes on Eock-fragments from the South of Scotland 

 imbedded in the Low-level Boulder-clay of Lancashire." By T. 

 Mellard Eeade, Esq., C.E., F.G.S. 



In his paper on the Drift-beds of the north-west of England, 

 Part IL Q. J. G. S. 1883, p. 119, the author noticed that the dis- 

 covery of Criffel-granite erratics in the Lancashire drift, first made 

 by Mr. Mackintosh, had been confirmed by Mr. P. Dudgeon, from 

 specimens forwarded by the author in 18^2. In August of last 

 year, he had an opportunity of travelling from Dumfries through 

 Kirkcudbright to Wigtonshire, and of examining the rocks and the 

 boulders derived from them. Two masses of granite have broken 

 through Silurian strata in Kirkcudbright ; the eastern of these 

 granite masses forms the isolated mountain of CritFel, 1800 feet 

 above the sea, the western rises to 2331 feet, and is known as 

 Cairnsmore of Fleet. The granite of the former is, as a rule, finer 

 than that of the latter. Numerous boulders derived from both are 

 found in the surrounding country. 



The author pointed out in detail how different varieties of granite 

 observed on Criffel and Cairnsmore of Fleet are clearly the rocks of 

 which fragments are found in the drift of Lancashire ; and also 

 showed that the Silurian " Greywackes," through which the granite 

 of the mountains named has burst, are also represented by unmis- 

 takable specimens in the Lancashire Boulder-clay. The " Grey- 

 wacke " varies in texture from a fine-grained sandstone to a coarse 

 gritty sandstone, and in colour from dark blue and grey to deep 

 purple-red. These beds, which belong to the Queensbury-grit 

 gravels, are well seen in a line of cliffs called the Craigs of Garheugh, 

 at the side of the road from Glenluce to Fort William. Specimens 

 identical with these rocks have been found in the low-level Boulder- 



