310 T. Mellard Reade— Glacial Geology. 



clay is perhaps the absence of lamination, so cliavacteristic of deposits 

 in water. But a consideration of the facts of the case suggests a 

 possible explanation. The two general causes of original lamination 

 — indeed I am not acquainted with any other — are the intermittent 

 supply of sediment, and the presence of flat plates of mica. Both 

 of these are probably absent in the case of the deposit in question. 

 The ice provides a continuous supply of rock flour, and rivers laden, 

 with it flow from the glacier and ice-sheet all the year through ; 

 and it permits the existence of no large flat plates of mica. 



The general conclusion, then, to be derived from a study of glacial 

 action seems to be that while the greater part of the rock-flour 

 which goes to form the clay is carried beyond the limits of the ice 

 and laid down in lakes, the sea, or on land, fringes and patches of 

 the same may be left behind in the valleys occupied by the glacier 

 or ice -sheet. 



V. — Glacial Geology : Old and New. 



By T. Mellard Reade, C.E., F.G.S., F.R.I.B.A. 



Historical and Personal. 



OYER twenty years ago I commenced the study of the glacial 

 deposits of the neighbourhood of Liverpool, and as the observa- 

 tions grew they came to embrace a considerable share of the drainage- 

 basin of the Irish Sea. 



I have personally inspected and kept full records of all of the 

 important artificial excavations likely to throw light upon the sub- 

 ject, in addition to examining and making sections of the natural 

 exposures of glacial drift which abound on the north-west coast of 

 England, the coast of Wales, and in the river valleys draining into 

 the Irish Sea, and to a lesser extent the drift on the east-coast of 

 Ireland and the south of Scotland. These observations, together 

 with others in districts outside the special area of my work, have 

 been communicated to various Societies and Magazines.^ 



This being my record, and glacial geology having during my 

 time gone through several phases, it may perhaps interest some of 

 the readers of the Geological Magazine if I give a resume of the 

 views I have been gradually led to adopt. 



1 Proc. of Liverpool Geol. Soc. 1872-73, pp. 31,32, pp. 42-65 ; 1873-74, 

 pp. 50-72. Q.J.G.S. vol. xsx. p. 27-41, 1874. Proc. of Liverpool Geol. Soc. 

 vol. iii. pt. 1, pp. 19-27, 1875. Geol. Mag. Dec. II. Vol. III. p. 480, 1876. 

 Proc. of Liverpool Geol. Soc. vol. iii. pt. 3, pp. 241-43, 1877. Geol. Mag. Dec. 

 II. Vol. IV. pp. 38, 39, 1877. Q J.G.S. vol. xxxiv. pp. 808-810, 1878; vol. xxv. 

 pp. 679-681, 1879. Proc. of Liverpool Geol. Soc. vol. iv. pt. 1, pp. 64-89, 1879 ; 

 vol. iv. pt. 2, pp. 139-153, 1880; vol. iv. pt. 3, pp. 216-233, 1881. Q, J.G.S. 

 vol. xxxviii. pp. 2'22-238, 1882. Trans. Geol. Soc. Glasgow, vol. vi. pt. 2, pp. 264- 

 276, 1882. Proc. of Liverpool Geol. Soc. vol. iv. pt. 5, pp. 364-380, 1883. Q.J.G.S. 

 vol. xxxix. pp. 83-132, 1883. Trans, of Liverpool Geol. Asso. vol. iii. pp. 93-101, 

 1883. Q.J.G.S. vol. xl. pp. 267-269; vol. xl. pp. 270-272, 1884. Proc. of 

 Liverpool Geol. Soc. vol. v. pt. 1, pp. 74-83, 1885. Q.J.G.S. vol. xli. pp. 102- 

 107 ; vol. xli. pp. 454-456, 1885. Proc. of Liverpool Geol. Soc. vol. v. pt. 4, 

 pp. 377-379, 1888. Nature, vol. xl. p. 246, 1889. Proc. Liverpool Geol. Soc. 

 vol. vi. pt. 2, p. 188, 1890; vol. vi. pt. 3, pp. 316-321, and pp. 333-4, 1891. 

 Geol. Mag. Vol. VIII. Dec. III. p. 291, 1891. Proc. Geol. Soc. 1892. 



