220 Geological Society: — Mr. Bowerbank on the 



2. The trap rocks occur at two points, one near the northern ex- 

 tremity of the peninsula, on the farm of Balscallock, constituting a 

 dyke of amygdaloid greenstone which cuts through the graywacke 

 and is lost in the sea ; and the other is near Loch Connell, where a 

 mass of greenstone extends in a westerly direction for nearly two 

 miles. At both localities, the trap intersects the graywacke ; but at 

 neither point could the author find it in contact with the coal or over- 

 lying breccia. 



3. Coal Measures. A deposit consisting of beds of red and white 

 sandstones, clays and micaceous shale, similar to those of the coal- 

 field of Ayr, has been long known to exist in the district, and has 

 led to several fruitless researches for coal. The deposit may be 

 traced for about nine miles, forming a narrow band parallel to Loch 

 Ryan. The beds are in general moderately inclined to the E. or 

 S.E. In a quarry on the farm of Clachan, Mr. Moore found re- 

 mains of Stigmaria ficoides, and in another, on the farm of Chal- 

 lock, an abundance of Calamites. 



4. Red Breccia. This rock extends from the bay of Sloughna- 

 garry to the farm of Dumlae, a distance of eight miles, forming a 

 ridge from 200 to 300 feet high, between the coal measures and the 

 shore of Loch Ryan. It consists entirely of irregular fragments of 

 graywacke cemented by a red clayey sand, but in some places it 

 passes into laminse of red sandstone. The beds are nearly horizon- 

 tal or dip slightly to the S.E., and rest on the coal measures. As Mr. 

 Moore did not detect any organic remains in the breccia, nor find 

 any rock overlying it, he does not offer an opinion respecting the 

 period of its formation. 



A paper was afterwards read, " On the Siliceous Bodies of the 

 Chalk, Greensand and Oolites ;" by Mr. Bowerbank, F.G.S. 



The author commences by stating, that naturalists and geologists 

 have long considered the form of tuberous masses of flint found in 

 the upper chalk to be due to alcyonia or sponges, but that he is not 

 aware of this opinion having been proved to b*e correct. It was 

 Professor Ehrenbcrg's observations on siliceous bodies which first 

 induced him to obtain thin slices of flint with the intention of pro- 

 curing specimens of Xanthidium. In the examination of these slices, 

 he was struck with the frecpient occurrence of patches of brown, re- 

 ticulated tissue, spicula and Foraminifera, and he was induced to 

 infer, that the patches of tissue were the remains of the organized 

 body, possibly a sponge, to which the flint owed its form. With this 

 belief, he commenced his inquiries by examining thin slices of flints 

 obtained from various localities, and he found in all of them, a per- 

 fect accordance in the structure and proportion of reticulated tissue, 

 in the number of spicula, and in the occurrence of Xanthidia and 

 Foraminifera. The following are the general appearances which the 

 slices of flint exhibit when mounted upon glass. 



With a power of about 120 linear, the slice i^resents the appear- 

 ance of a stratum of a turbid solution of decomposed vegetable or 

 animal matter containing Foraminifera, spicula, Xanthidia, and fre- 

 quently fragments of the brown tissue. In a specimen from North- 



