96 SIXTH REPORT — 1836. 



stones of various colours and micaceous flagstones. These silicious 

 rocks alternate with incoherent slates, and are in some places sur- 

 mounted by gi'eat masses of red unctuous shale, which, when in a more 

 solid form, generally exhibit cleavage oblique to the stratification. 



5. The lower part of the Silurian system rests conformably on 

 the preceding, and on the north-western coast, near Barnstaple, con- 

 taining subordinate beds of limestone. In its range towards the eastern 

 part of the county it gradually thins off, but its characters are well 

 presen'ed, and it contains some characteristic organic remains. 



6. The carbonaceous system of Devonshire ranges in a direction 

 east and west across the county, in its southern boundary so close to 

 Dartmoor, that its lower beds have been tilted up and altered by the 

 granite. It occupies a trough, the northern border of which rests partly 

 in a conformable position upon the Silurian, and partly upon older rocks, 

 probably of the division No. 4. Its southern border also rests on the 

 slate rocks of South Devon *. It everywhere exhibits a succession of 

 violent contortions. In some places it is overlaid by patches of the 

 Green Sand formation, and west of Bideford by conglomerates of the 

 New Red Sandstone. The lowest portion of this vast deposit is gene- 

 rally thin-bedded, sometimes composed of sandstone and shale, with 

 impressions of plants, sometimes of indurated compact slate, containing 

 toavellite. These beds are surmounted by alternations of shale and 

 dark-coloured limestone with a few fossils. Subordinate to these, on 

 the western side of the county, are thin veins and flakes of culm or an- 

 thracite ; but this is wanting on the eastern side, and the calcareous 

 beds are more expanded. The higher beds of this deposit are well 

 exhibited on the coast west of Bideford. These often contain impres- 

 sions of vegetables. 



Though in a state of greater induration than the ordinary coal-mea- 

 sures of England, and even in many places destitute of coal, these beds do 

 not differ from the great productive coal or culm field of Pembrokeshire. 

 The authors consequently concluded, that from the order of superpo- 

 sition, — from mineral structure — from absence of slaty cleavage pecu- 

 liar to the older rocks on which it rests — and from the specific character 

 of its organic remains — this deposit may without hesitation be referred 

 to the regular carboniferous series. 



In the course of the details a remarkable elevated beach was alluded 

 to, occupying two miles of coast, on the north side of Barnstaple Bay, 

 a more special account of which has since been prepared for the Geolo- 

 gical Society. 



On the Site of the Ancient City of Memphis. By the Maequess Spineto. 



The author read a paper, entitled, " A Report of the Attempts made to 

 ascertain the Latitude of the Ancient City of Memphis :" he considers 

 the site of this city as having been in the present bed of the Nile, in 

 latitude 29° 46' north, and longitude 31° 30' east from Greenwich. 



* The authors have since read a Memoir before the Geological Society, on the gene- 

 ral structure of Devonshire, in which the age of the strata of South Devon is pointed 

 out. 



