Report on the 21oel Tnjfaen Drift. 



117 



4. Eeiglt of RocJc Surface.— The floor of Gallery " No. 1," the 

 highest in the Alexandra Quarry, is at 1,281 feet above sea-level. 

 The surface of the rock emerges from below drift in the floor of 

 this gallery a few yards E.S.E. of the edge of the Boulder-clay, and 

 rises gradually to W.N.W. The angle measured by Abney Level 

 from the opposite side of the Alexandra Quarry is from 2°-5 to 6°'0 

 (average 4°-25) to E.S.E. (Photographs 1, 2, 3). But the surface 

 undulates (Photographs 7, 8). 



5. Slope of Surface of Drift along Section (Photograph 3). 



6. Strike 'and Dip of Cleavage of Slates.—^. 30 E., 95°-98° to 

 S. of E. Dip of Bedding of Slates.— 25°-S0° S.S.E. or S., but 

 undulating. 



7. Thickness of Drifts along Section. — 25 feet maximum, thinning 

 toward hilltop (Photographs 1, 2, 3, 4, 11). The sections which 

 will remain at present will show the varying thicknesses in the 

 quarries. 



8. General Nature of the Drifts. — Their general characters have 

 been often described. Towards the N.W. are sands, sandy loam, 

 and gravel, with shells, Boulder-cla}'^ coming on above them towards 

 the S.E. (Photographs 1, 2, 3). 



9. Position of Bonndartj of Sandy Group and Boulder-clay. — The 

 junction at the surface between the quarries is about 1,000 feet from 

 the hilltop. 



/. Mynydd MawrEurite 

 2 Welsh Fefsite 



3. Penm^nmur Dhrite 



fro/7 pan 



Fig. 2. — Contortions in Sands below Boulder-clay. 

 (Section at x in Fig. 3 on Elevation.) 



10. Character of the Sandy Group. — The beds may be described 

 as sand and yellow loam with gravelly streaks and pockets 

 containing shells. The shell fragments were found on November 5 

 only in the gravel, none but the finest crumbs having been seen 

 in the sand and loam (a, p. 120). The bedding is very irregular, 

 and even here and there curved (Photograph 1), but contortion has 

 only been observed near the junction with the overlying Boulder- 

 clay (/i, p. 120). 



11. Characters of the Boxdder-clay. — This is a good typical, tough, 

 strong, unstratified till, such as is mostly found in mountain 



