Reviews. — Geological Map of London. 231 



figs. 4, 5, 6, 7, 12, and 13, all referred to Acacia, are probably 

 correctly determined, and represent species of the groups GummifercB 

 and Vulgares, both of which are at the present day abundant in Africa. 

 Fig. 4, indeed, if the leaves of figs. 1 and 2 really belong to it, 

 must be very near to the A. catechu of the present day. The pods 

 figs. 20 and 21, are determined as Mimosece ; but if I had had such 

 pods shown to me in a fresh state, I should have referred them 

 without hesitation to Acacia. Fig. 20 is exceedingly like the pod of 

 A. constricta from the United States, and very near to that of a few 

 very narrow-fruited gummiferous Acacioe, of Africa, as well as to 

 some of the Australian. Pliillodinem. Fig. 21 is very like the pod of 

 several Acacice of the group Vulgares, which, when rotting, often 

 break up irregularly, as shown in the drawing. Both are very 

 unlike any .Mmosa-pods known to me. In this genus the lines 

 separating the articula of the valve are always quite straight, and at 

 right angles to the margin. Figs. 8 and 9, referred to Acacia, are more 

 like the pods of some species of Cassia. Figs. 23 and 24 may repre- 

 sent Albizzia-Tpods. Fig. 22 may be an Entacla, as determined, though 

 not any recent species; but it is also nearly as much like some 

 Ormosia-jiodLs. Both these genera are still represented in Africa. 



EEYIE W S, 



I. — Geological Map of London and the Neighbourhood. 



THE publication by the Geological Survey of a Map with London 

 as a centre, will be hailed with satisfaction by those interested 

 in the geology of the metropolis, and of the country within easy dis- 

 tance around it. Formerly one had to procure four distinct sheets of 

 the Geological Survey Map of England, in order to obtain the whole 

 of London geologically coloured, and then one obtained actually 

 more than was necessary for the illustration of London geology or 

 convenient as a diagram for the wall of the library. The present 

 Map embraces an area bordered on the North by Blackmore, Epping, 

 Waltham Abbey, Potter's Bar, Watford, and Chesham Bois ; and on 

 the West by Amersham, Windsor, Chertsey, and Cobham ; on the 

 South by Epsom, Croydon, Farnborough, and Shoreham ; and on 

 the East by Gravesend, Grays Thurrock, Brentwood, and Frierning. 



The Map is published both with and without drifts ; but it need 

 hardly be said that for most practical and scientific purposes the 

 map showing drifts is alone desirable, for no geological map on a 

 scale of one-inch to a mile can be considered complete if the super- 

 ficial deposits be omitted. Their influence on the scenery of the 

 district is trifling, for the main features were sketched out before the 

 drift deposits were laid down : they rest indifferently upon the 

 Tertiary strata and Chalk, and yet many of them, and particularly 

 the Glacial Deposits, have suffered much denudation. 



The formations represented include the Chalk, Thanet Beds, 

 Woolwich and Beading Beds, Oldhaven Beds, London Clay, and 

 Bagshot Beds. The Drift deposits, which are entitled equally to 



