404 Geological Society. 



ing to parts of huge polygons broken up into small ones, as if the 

 surface of the earth had once formed part of a basaltic causeway. 



Several charts, plans, and drawings were provided by the author 

 in illustration of the paper. 



2. " On the Ludlow Bone-bed and its Crustacean Remains." By 

 J. Harley.M.B. 



Of the two bone-beds occurring near Ludlow, the lower one (seen 

 in Ludford Lane and on the north-east slopes of Whitcliff) is that 

 which has supplied the author with the materials for this paper. 

 Besides spines, teeth, and shagreen-like remains of fish, the author 

 finds in the Ludlow Bone-bed three kinds of minute organisms : 

 1st, conical bodies, the same as the " Conodonts " of Pander ; 2ndly, 

 bodies somewhat like the crown of a molar tooth ; 3rdly, oblong 

 plates. All these bodies possess the same chemical composition and 

 microscopical structure — which is decidedly Crustacean. With 

 Pterygotus they do not appear to have any relationship, unless some 

 are the stomach-teeth : nor do they show any alliance with Trilobites ; 

 but with Ceratiocaris they have a great resemblance as to structural 

 characters, and some of them were probably the minute secondary 

 spines of the tail of that Phyllopod. The plate-like forms might have 

 belonged to Squilloid or Limuloid Crustaceans. To facilitate the 

 recognition of these bodies, Mr. Harley places them all in one pro- 

 visional genus with the name of Astacoderma. A letter from Dr. 

 Volborth to the author was also read in confirmation of Mr. Harley's 

 opinion that these bodies are identical with Dr. Pander's " Cono- 

 donts." Numerous original drawings illustrated the paper. 



3. "On the Old Red Sandstone of Forfarshire." Bv James Powrie, 

 Esq., F.G.S. 



The author described the series of stratified rocks belonging to 

 the Old Red Sandstone, upwards of 3000 feet in thickness, stretching 

 southward from the Grampians to the coast of Fifeshire. 1st. Dark- 

 red grits (with cornstones and flagstones) equivalent to the English 

 " Tilestones." 2ndly. Thick conglomerates and the Arbroath paving- 

 flags : Pterygotus anglicus, StyIo?iurus, Parka decipiens, Cephalaspis, 

 Biplacanthus gracilis, and other fossils belong to this part of the 

 series. 3rdly. Thick-bedded red sandstone (with cornstone) : Cepha- 

 laspis and Pteraspis. 4thly. Soft deep-red sandstones, othly. 

 Spotted marls and shales : these are the uppermost, and may be the 

 equivalent of the Holoptychian beds of Clashbinnie. The author 

 showed that between the Grampians and the trappean hills of Bun- 

 nichen and Bunbarrow the series forms a great syncline ; and be- 

 tween these hills and the sea the older beds are twice again brought 

 to the surface ; and he believes that the marls and sandstones at 

 "Whiteness are not unconformable, as Sir C. Lyell has represented 

 them in his published section. 



4. The Secretary gave a brief account of the discovery of an ex- 

 posure of sandstone strata with two bands of clay full of calcareous 

 nodules containing plentiful remains of Coccosieus, Giyptolepis, and 

 other fishes belonging to the Old Red Sandstone, in a burn about 

 2^ miles from the Manse at Edderton, Ross-shire, on the south side 



