174 Reviews—Hopkinson’s Geology of Hertfordshire. 
ought hardly to have been passed by. Godwin-Austen’s classical 
memoir might have suggested some points of importance in dealing 
with the Carboniferous rocks; there is not absolute unanimity 
amongst geologists as to the abyssal origin of the Chalk, or about 
the Miocene age of the Bovey lignites; while the height of Moel 
Tryfaen is generally given as 1360 and not 1170 feet. 
The book suffers also from many misprints; there is hardly a 
fossil list without one; we often have ce for «, and we meet with 
artica, C. elaphas, Rhynconella, Anchyterium, Cristeltaria, Nautali, 
Archeopterix, Belemintes, E. liliiformiss, etc. We cannot help 
closing the work with a feeling of disappointment that a capital 
opportunity has been missed of presenting to untechnical readers 
a readable and yet thorough and scientific “Sketch of Geological 
History.” 
V.—A SKETCH oF THE GEOLOGY AND CLIMATE OF HERTFORDSHIRE. 
By Joun Hopkinson, F.L.S., F.G.S., Treas. Geol. Assoc., V.P. 
Herts Nat. Hist. Soc. (Hertford, printed by Stephen Austin and 
Sons, 1887.) 
HIS is an extract from the Introduction to the “ Flora and Fauna 
of Hertfordshire,” by the late R. Pryor, B.A., F.L.S., which 
now appears in a separate form as a small quarto of 52 pages, 
together with a coloured map of the county showing its river basins 
as adopted for the Botanical Districts. The interest is largely 
meteorological and botanical, but the whole structure is laid on a 
geological foundation. This part of the subject is illustrated by two 
maps, the first of which shows the superficial geology—Alluviun, 
Boulder Clay, Gravel and Sand chiefly Glacial, Brick-earth, Clay 
with flints and occasionally Brick-earth, Pebble Gravel, and lastly 
Eocene and Cretaceous. Although, of course, one or other of the 
two latter underlies the entire surface of the county, both are so 
largely masked by superficial or “drift” beds that the second, or 
agricultural, map is mainly influenced by the development of these 
superficial beds. Doubtless many of these facts are well known to 
students of the various Memoirs dealing with the London Basin, 
but Mr. Hopkinson has his own way of telling the story, and he 
contrives to put a considerable amount of useful matter before his 
reader within the limits of a very few pages. The chapter on 
Hydro-geology is especially interesting, and in view of the impending _ 
drought may well attract attention. The Botanical Districts would 
seem to coincide with the river systems. I. Drainage of the Ouse: 
1 Cam, 2 Ivel. IL. Drainage of the Thames: 3 Thame, 4 Colne, 
5 Brent, 6 Lea. The first three are outside the London Basin and 
together constitute not more, perhaps, than one-eighth of the county. 
W. H. H. 
