Keywords: The Quarterly journal of the Geological Society of London (13859759305).jpg <br> 12 Explanation oe the Section at the Bay of Nigg <br> Pig 3 � Section of Mud Cliff at Bay of Nigg <br> Depth of section about 60 feet ; length of do about 200 yards <br> 6 x <br> l l <br> 1 Gneiss 2 Gravel 3 Grey Boulder-clay <br> 4 Bed Boulder-clay 5 Sandy silt 6 Moraine gravel <br> 1 The rock at the base is a coarse granitic gneiss not much <br> exposed and so far as I can see exhibiting no clear marks of glacia- <br> tion <br> 2 The lower gravel is a very unusual feature in this quarter as <br> it is seldom that any thing is found between the rock and the grey <br> Boulder-clay above it This gravel is seen only at the south end of <br> the section Where it commences at the base of the cliff it is very <br> coarse with a few large boulders of granite and gneiss from 3 to <br> 5 feet in diameter ; but as it rises and thickens in the bank it ceases <br> to contain any large boulders and consists of waterworn pebbly <br> gravel and sand the stones being well rounded ; in mineral quality <br> they consist of granite and gneiss similar to what occur in the grey <br> Boulder-clay above This lower gravel cannot be traced for any great <br> length beyond the section the rocks along the coast to the south- <br> ward being covered by Boulder-clay I could see no trace of shells <br> in this gravel which reaches a thickness of from 10 to 20 feet at its <br> southern extremity <br> 3 The Boulder- clay which forms the chief mass of the section is <br> of a dull grey or dun colour is very compact firm and difficult to <br> pierce stands up like a wall with a perpendicular or even over- <br> hanging front 30 or 40 feet high although washed at the base by <br> the surf at high tide At the south end of the section it thius off <br> considerably and rests on the gravel no 2 In one place near the <br> middle of the section it rests on a small knob of gneiss ; but further <br> north its bottom is not exposed It is quite unstratified very tough <br> and solid as if it had been compressed beneath a heavy weight and <br> contains no broken shells or organic remains of any kind so far as <br> I could perceive The stones in it are of granite and gneiss of <br> several varieties with some of quartz-rock hornblende-schist <br> felspar-porphyry and greenstone the last not common These stones <br> have their angles worn off and are generally of small sizes ; but <br> some large boulders from 3 to 4 feet in diameter occur here <br> and there in all parts of the mass ; and still larger ones are seen at <br> low water along the base of the cliff which have no doubt been 36935950 113692 51125 Page 175 Text 38 http //www biodiversitylibrary org/page/36935950 1882 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 38 1882 Geology Periodicals Smithsonian Libraries bhl page 36935950 dc identifier http //biodiversitylibrary org/page/36935950 smithsonian libraries Information field Flickr posted date ISOdate 2014-04-15 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13859759305 2015-08-26 07 57 38 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1882 Photos uploaded from Flickr by Fæ using a script |