TRANSACTIONS OF THE SECTIONS. 67 



on one side bv the range of high hills known as the North Mountain, and on the 

 other by the northern termination of the hills of the Devonian series. They un- 

 derlie one of the most fertile districts in the colony. 



There are evidences in this locality of extensive denudation. The sandstone is 

 found high up on the sides of the abrupt termination of the trap hills already 

 referred to, and is mingled with the igneous rocks on the face of Cape Blomidon, 

 far above the level of the surrounding country. 



They have not been found in Nova Scotia to contain any fossil remains. In 

 Prince Edward Island there have been obtained from them some specimens of 

 fossil wood, and the jawbone, together with seven teeth, of a Saurian reptile, 

 named by Dr. Leidy, of Philadelphia, Bathygnaihua borecdis. These would appear 

 to point to the Permian period of Europe as the probable time of its formation. 



This is confirmed from another source. The trap associated with them was 

 upheaved after the whole formation had been deposited. This trap seems to be 

 of the same age as the trap of New Brunswick and that of the Alleghany Moun- 

 tains in America, an extension of which runs eastward through Lower Canada as 

 far as the Day of Chaleur, where there is found associated with it red sandstone beds 

 similar to those described above. The red sandstone of the Connecticut river- 

 valley was deposited after the upheaval of the Alleghany Mountains, for it rests 

 unconformable upon the upturned edges of carboniferous strata disturbed by the 

 igneous outburst. It necessarily follows, therefore, that the red sandstone of the 

 eastern provinces and those of Connecticut are of different ages, the former being 

 earlier, and the latter later, than the trap hills and mountains referred to. The 

 red sandstone of Nova Scotia was first deposited, then followed the trap up- 

 heaval, and when the disturbance had subsided, the red sandstone beds of Con- 

 necticut were laid down. 



The colour of these beds seems to be derived from the iron contained in the 

 neighbouring metamorphic rocks. It occurs in these latter in three different forms. 

 1, There is a quantity of it distributed generally throughout the slate and shale, 

 of which these strata are composed ; 2. there are veins and beds of specular 

 iron ore, as in the Devonian rocks of Nictaux ; and 3. it occurs in the shape of 

 bisulphide of iron or iron pyrites. When these metamorphic rocks were worn 

 away, the iron set free was oxidized by contact with the atmosphere, and mixed 

 up with sediment as it was laid down. 



On some Fossiliferous Strata occurring between the Bunter Sandstone and 



Mountain Limestone of the Vale of Clwyd, North Wales. By George Maw, 



I.SJL., F.G.S. 4- F.L.S. 



The Ordnance Geological Survey map places the Bunter sandstone, occupying the 

 vale of Clwyd throughout its boundary, either adjacent to the mountain limestone, 

 or to the Denbighshire shales and grits. In several places along its eastern side strata 

 intervene, consisting of mottled sandstones, variegated shaly marls, containing plant 

 remains and dark micaceous sandstones. The marly shales abound with plant im- 

 pressions, which Mr. Etheridge, palaeontologist to the Survey, considers to be of a 

 Permian type, and unlike carboniferous forms. These beds are for the most part 

 conformable to the mountain limestone, dipping unconformably under the brick-red 

 Bunter sandstone towards the vale of Clwyd. In lithological aspect they strongly 

 resemble Permian strata. The principal localities where they are exposed are at 

 Pentre celyn, near Llanfair, in the wood above Llandibr Farm, and in a lane between 

 Llandibr Farm and Llangynhafal. Bed and variegated marls and marly shales, 

 containing some soft coal, and resting on the mountain limestone, occur also at 

 Rhiwbibill near Llangwyfen, opposite Denbigh. Although apparently conformable 

 to the carboniferous limestone, it is probable that they rest on its eroded surface. 



The millstone-grit is developed in great massiveness within four and a half 

 miles to the east of Pentre celyn, and a small outlier crops up in the Vale of Clwyd 

 at Ty Coch, a mile and a half to the north. Its absence at Pentre celyn could not 

 be accounted for from the thinning out of its mass within so short a distance, or 

 excepting from erosion : if a break really occurs, the marls and shales resting on 

 the limestone coidd not be of carboniferous age. 



