Geological Society of Glasgow. 291 



The author referred the whole of the rocks treated of, with the 

 exception of the purple and greenish grits of St. Breock's Down to 

 the Middle Devonian System, and considered that if the lower or 

 Linton rocks were to be met with at all on the south side of the 

 Culm-trough, it would be in the high ground which forms the 

 watershed of West Cornwall. 



In the concluding portion of the paper. Dr. Holl entered upon the 

 palseontological relations of the different South Devon Groups, and 

 especially those of the Petherwin beds. 



Geological Society of Glasgow, April 2nd, 1868. — The fol- 

 lowing papers were read : — 



I. '* On the Post-Tertiary Beds of Scotland." By the Eev. Henry 

 W. Crosskey and Mr. David Eobertson. 



This paper dwelt upon the necessity of a classification of the Post- 

 Tertiary beds, both on physical grounds and with reference to their 

 fossil contents. Five distinct classes of Post-Tertiary beds were in- 

 dicated. (1) Clays indicating the extreme range of cold, and with 

 the most intensely Arctic fauna. Among these may be placed the 

 beds at Errol, Dalmuir, Paisley, Stevenston, Lochglip, Kilchattan, 

 and others. At a new bed lately investigated, near Millport, the 

 plates of an Echinus, new to science, have been found. The authors 

 obtained the same plates from some old beds in Norway, but are not 

 aware of its occurrence in any other localities. (2) Clays indicating 

 a moderate depth of water, and largely Arctic, but not so intensely 

 northern as the preceding. Many of these clays crop out at half 

 tide at numerous places in the Frith of Clyde, and the upper parts 

 of many of the clay-pits, which have, in their lower parts, the most 

 arctic fauna, may be ranked in this class. (3) Clays and sands 

 denoting an increase of warmth, which continued until, very possibly, 

 even a higher temperature than at present prevails, was reached. A 

 typical bed of this class occurs in the Kyles of Bute. (4) Clays and 

 sands in which the fauna approaches very nearly to that now preva- 

 lent — the only difference being in the proportion of various species. 

 Examples of this class may be seen in the lower part of the section 

 at Irvine Water and the Ostrea bed near the Bridge of Allan. (5) 

 The more recent raised beaches — common along the whole coast. 

 It is most important that a complete list of species should be drawn 

 up for every separate locality, and the authors propose to insert some 

 special catalogues they have prepared, in the next part of the Trans- 

 actions of the Society. 



II. " On the Surface Geology of the District round Glasgow, as 

 indicated by the Journals of certain Bores." By Mr. James Bennie. 

 — The object of this paper was to communicate the results obtained 

 by the study of the surface portions of certain bores lately made for 

 minerals, in order that the attention of geologists might be directed 

 to this mode of research, as capable of supplementing natural sections, 

 which are often imperfect from not exhausting the surface deposits ; 

 and also in directing inquiry into interesting localities, which, from 

 the surface being flat, nothing could be known except by direct 

 boring. 



