BRITISH ISLES. 25 



the action of varying currents in an estuary at different levels. The 

 direction of the currents wearing away the clay bands and depositing 

 the galls and sand is suggested ; and these observations are offered as 

 further materials in working out the hydrography and history of the 

 Lower Tertiaries. , T. K. J. 



Judd, Jolm W. On the Structure and Age of Arthur's Seat, Edin- 

 burgh. Quart. Journ. Geol. Soc. vol. xxxi. pp. 131-148, 4 wood- 

 cuts (sections). 



It has usually been supposed that the peculiar features of this hill 

 can only be explained by the hypothesis that two series of volcanic erup- 

 tions, widely separated in time, had occurred upon the same site. A 

 re-examination of the evidence, however, shows that all the phenomena 

 can be accounted for by a single series of volcanic outbursts, during the 

 period of the formation of the Lower Carhonifer-ous (Calciferous Sand- 

 stone) in Scotland. The relation of the outbursts of volcanic violence, 

 which produced Arthur's Seat, to the contemporary eruptions in the 

 Central valley of Scotland is described. J. W. J, 



. The Geology of Eutland and the Parts of Lincoln, Leicester, 



Northampton, Huntingdon, and Cambridge included in Sheet 64 

 of the one-inch Map of the Geological Survey ; with an Introduc- 

 tory Essay on the Classification and Correlation of the Midland 

 District of England. Appendix, with Tables of Possils, by R. 

 Etheridge. Pp. xv, 320, 11 plates (sections and views), 19 

 woodcuts. Geolofjical Survey Memoir. 8vo. London. 

 The Introductory Essay " On the Classification of the Jurassic Strata 

 of the Midland District and their Correlation with those of the Cottes- 

 wold Hills and the Xorth-east of Yorkshire," takes up pp. 1-52. — 

 Chap. i. Physical Features, 53-56. — ii.-iv. U., M. and L. Lias, 57-89. 

 — V. L. Oolites, 90-112. — vi. Origin of the Northampton Sand (General 

 Features, Lithological, MicroscojHcal, and Chemical characters, Mode 

 of Formation, Causes of Redistribution of the Iron), 113-138. — vii. 

 Lincolnshire Limestone and CoUyweston Slate (Notices of the building- 

 stones, and Origin of the Oolitic Structure), 139-185. — viii. Gt. 

 )olite (The Estuarine Series, Limestones, Clays, Cornbrash), 186-231. 

 — ix. M. Oolites, 232-239.— x. Post Tertiary Deposits (Pre-Glacial, 

 Glacial, Post-Glacial), 240-253. — xi. Position and Disturbances of the 

 Strata, 254-259. — xii. Miscellaneous (Denudation, Scenery, Springs, 

 &c.), 260-271.— Appendices : i. Lists of fossils, 273-292. (There are 

 many local lists throughout the book.) ii. Bibliography of the Dis- 

 trict, 293-301. W. W. 



Jukes-Browne, A. J. On the Relations of the Cambridge Gault and 



Greensand. Quart. Journ. Geol. Soc. vol. xxxi. pp. 256-316, 



pis. xiv, XV (fossils), 5 woodcuts (map and sections). 



Regards the Cambridge Greensand as the base of the Chalk-Marl, 



it having been formed from the erosion of the Gault by marine currents. 



Where the "Greensand" bed exists the true Upper Greensand is absent 



