7th January 1875.

DR. RAMSAY H. TRAQUAIR, Vice-President, in the Chair.

The following Communication was read:

On the Wardie and Granton series of Sundstones and Shales. By JOHN HENDERSON.

The series of rocks comprising what are known as the Wardie Shales and Granton Sandstones have long been familiar to geologists. Even before any attempt had been made to describe them stratigraphically-and indeed very little has yet been done in this direction by any of our local geologists-the attention of geologists had been directed to them from the interesting character of their organic remains.

Maclaren, in his admirable work, "The Geology of Fife and the Lothians," only notices them in one or two general sections across the district; nor can we expect much local detail in a work which embraces the geology of so large an extent of country. The first attempt to connect the strata of the district by tracing their course inland is to be found in the "Memoir of the Geological Survey of the Neighbourhood of Edinburgh," sheet 32, by Messrs Howell and Geikie; but it is evident the same remark applies to this work as to Maclaren's, namely, that the limited space at their command did not admit of a more detailed description of the beds. Nor can we find fault with this, provided the description is in the main correct.

In dealing with these rocks, I shall begin by describing a series of transverse sections of the district, and by tracing the beds inland, attempt to connect the different sections, and show the relation of the whole series from bottom to top. Beginning with the north end of the district, along the shore from Granton quarry on the west to near the chain pier at Trinity on the east, a distance of about two miles (see Map and Section No 1), we have a nearly continuous section exposed. At Granton quarry the sandstone beds scarcely reach the surface, and are covered by a considerable thickness of black shale, which seems to arch over the top of the sandstones, forming an anticline at this part. As we trace the series eastward from Granton quarry, we find the rocks assume a steady dip to the east, at angles from 20° to 30°. The beds seen are mostly sandstones in thick courses, which run in ridges into the sea, forming bays between. Very little rock is exposed within these bays, but at low water several exposures occur, showing that the rocks within these bays are mostly thin

A Granton Sandstone B.Sandstone and Shales lynny between the Granton and Craigleith Sandstone. C. Craigleith Sandstone D. Wardie Shales ESundstone and Shale with abundant plant remains FShales of Slateford and Kate's Mill GSandstones of Hailes and Redhall H.Shales overlying Redhall and Hailes.

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bedded sandstones, and shales dipping in the same direction as the thicker bedded sandstones. Three or four of these bays occur between Granton quarry and the west breakwater at Granton, showing as many courses of alternating shales and sandstones.

At Carolina Park gate, a thick course of sandstone has been quarried; it likewise forms the ridge called General's Rocks, which runs for a considerable distance into the sea at this point. This seems to be the uppermost course of thick-bedded sandstones in this section; above them comes a series of fine black shales dipping steadily eastward, these continue for about one hundred yards, and form what might be termed the base of the famous Wardie Shales. Above this we have several feet of sandstone, and above this again a bed of fireclay almost identical with the fireclay of the Coal Measures. I was so much struck with its resemblance that I examined the upper portion of it to see if any coal existed, and found a bed of coal upwards of a foot thick, and above this again another bed of fireclay overlaid by a bed of coal about nine inches thick; overlying these are beds of sandstone and shale, into which intrusive beds of igneous rocks have been injected, hardening and cutting through the beds in many places, the whole forming a very interesting section.

Between these and Trinity the whole series rise and fall in many undulations, forming several.anticlines and synclines; and although the whole series of shales extends for upwards of a mile, I do not think that they show a greater vertical thickness than about four hundred feet or thereby. It will be in the recollection of some of the members of this Society that a number of borings for coal were carried on along the top of the terrace that forms a raised beach in front of Wardie and Granton. Maclaren mentions one or two made by Captain Boswell on his estate there, where the workmen passed through two beds of coal 200 feet below the level of the sea. I have no doubt that these are the same beds that crop out behind the west breakwater. We often hear of the foolishness of people boring these lower rocks for coal; but it appears strange to me that they should bore in this locality, when the whole section, down through the thickbedded sandstones of Carolina Park, is exposed along the shore. If anything is plain in this section, it is the fact that the Wardie shales overlie the Granton sandstones. In the "Memoir of the Geological Survey," sheet 32, the Granton and Craigleith sandstones are stated to overlie the Wardie shales; but no proof is offered that such is the case, whereas the section here clearly proves the contrary. The vertical thickness of this section from the sandstones of Granton quarry to the top of the Wardie shales may be about 1800 feet. The general strike of the beds is north and south. In tracing the beds inland, a good deal of

difficulty is experienced owing to the deep covering of drift which extends over the district, but what with borings, railway cuttings, quarry workings, and river sections, I have been able to follow up the beds in the line of strike, and find the representatives of the shore section about two miles inland. If we take the centre of the section at the base of the Wardie shales, where the strike appears to be most persistent, and prolong the line for about two miles inland, it will pass a little to the east of Craigleith quarry. The sandstone here has been quarried to a depth of about 200 feet, and dips to the east at an angle of about 20°. From what I have been able to make out from sections and borings, &c. between the shore and Craigleith, I am confident that the Craigleith sandstones are a continuation of the sandstone beds forming the general rocks at the base of the Wardie shales. Above the sandstones of Craigleith a series of shales is exposed, also dipping east, which must represent the base of the Wardie shale series. A transverse section through this part of the series was described and figured by me in a paper published in the "Transactions" of our Society, vol. ii. page 29. The beds underlying the Craigleith sandstones can be traced westward at various points, such as at Blackhall, Ravelston and Craigcrook, where they arch over and dip west under the igneous rocks of Corstorphine Hill. In carrying our section eastward we have to go some distance south, where, in the bed of the water of Leith at the back of Donaldson's Hospital, we find shale-beds of a considerable thickness dipping west, forming a synclinal axis between this and Craigleith; from this point we can trace the beds eastward, in a descending order in the bed of the water of Leith, to near the Dean Bridge, where the shales are underlaid by about 200 feet of sandstone, which I consider to be the equivalent of the Craigleith beds. Below these sandstones about 100 feet of shale are exposed at the Dean Bridge, which are again underlaid by beds of sandstone. The section cannot be traced further east in the bed of the water of Leith, but I have been able to trace it downward from cuttings made for building and draining operations at the west end of Edinburgh eastward to the Castle Hill, and I find that it consists of alternating beds of sandstones and shales dipping west at angles varying from 20° to 30°. From the shale-beds in the water of Leith behind Donaldson's Hospital to the Castle Hill is about one mile, and taking the dip at about 20°, would make a vertical thickness of about 1700 feet; but this does not show the whole thickness of the series downwards; for beds of sandstone and shale, with a westerly dip, have been exposed at various parts of the New Town eastward to St Andrews Square.

Now, one thing is plain by this section, namely, that the rocks between the Castle Hill and Corstorphine are bent into a