120 
THE GEOLOGIST. 
of each stratum. The collection is, as our readers well know, arranged on 
a stratigraphical plan ; and by the use of coloured tablets, in walking past 
cases we see at a glance the fossils we ought to find in any ordinary lo- 
cality of every geological formation. To the student this is a facility of 
the highest value, and enables him, whether studying for a class or pre- 
paring for a full excursion, to learn with certainty and ease the essentially 
typical fossils of every stratigraphical group or of the district he is visiting. 
JSot a less happy idea was it to illustrate or rather to explain the map- 
sheets of the Survey, by short memoirs of the geology of the dis- 
tricts they represent. Thus, the fluvio-marine beds of the Isle of Wight 
have been described by Edward Forbes ; the country round Chelten- 
ham, by Mr. Hull ; parts of AYiltshire and Gloucestershire, by Profes- 
sor Eamsay ; the South Staffordshire Coal-field, by Mr. Jukes ; the War- 
wickshire Coal-field, by Mr. Howell ; the country round Woodstock, the 
country round Prescot, in Lancashire, parts of Oxfordshire and Berkshire, 
p,nd the AV'igan Coal-field, by Mr. Hull ; part of Leicestershire, and parts of 
!Northam]3t on shire and Warwickshire, by Mr. Aveline. The West Indian 
surveyors have followed this excellent example, and we have had a me- 
moir on the geology of Trinidad, by Messrs. Wall and Sawkins. 
Two others just issued are before us, ' The Geology of Parts of Oxford- 
shire and Berkshire (Sheet 13),' by Messrs. Hull and TVTiitaker ; and ' The 
Geology of Parts of Berkshire and Hampshire (Sheet 12),' by Messrs. 
Bristow and Whitaker. 
The Geologists' Association are about to take again their summer ex- 
cursions : how admirably instructive it would be to take one of those geo- 
logical spots in Berkshire or Hampshire, which Mr. Bristow so faithfully 
and accurately describes in this little eightpenny Memoir ; and with the 
geological map of the district, Mr. Bristow's descriptions of the sections 
and other exposures of the strata, of their order, sequence, and mineral 
characters, and Mr. Etheredge's lists of fossils, how much more instruction 
would be got out of some of those pleasant hohdays than can ever be at- 
tainable under the best desultory leadersh'p ! 
In Mr. Hull's ' Oxfordshire' a small coloured geological map is inserted, 
reduced by photography from the larger Ordnance sheet, so that we have 
in it map and text for a week's good geological labour. In Mr. Bristow's 
Memoir, the cretaceous rocks and tertiaries from the Eocene of Woolwich 
and Keading to the alluvium of the Kennet, is treated in a masterly man- 
ner, and illustrated by well selected woodcuts. The CTetaceous deposits 
and tertiaries, as also the oolitic series, form the topics of Mr. Hull's 
' Memoir on Oxfordshire and Berkshire,' and, we need scarcely say, are 
treated in an equally able manner. 
