1897] SOME NEW BOOKS ay 
Page after page attests the energetic field-work on which each series 
of results is based, though now and then acquaintance with the 
ground is required, before we can detect how much is due to a grasp 
of the features of the scene itself, and how much is culled from the 
drier field of published memoirs. 
We wust not attempt, chapter by chapter, to touch on the 
numerous new suggestions, or the revisions of previous work, con- 
tained in the description of each special area. On p. 145, we note 
that the Cambrian is stated to pass down conformably into the 
Pebidian of St David’s, which is included with it, the Arvonian and 
Dimetian being intrusive ; and no pre-Cambrian rocks are tolerated 
here. But in other places the earlier work of the survey is candidly 
set aside, where the personal investigation of the author has led to a 
change of view. Here and there, work remaining to be done is 
indicated, as in the Malvern range (p. 170), and in the important 
Borrowdale series (p. 227). 
In the latter case, the discussion given in the present work does 
much to fill the gap, and is a fine example of the caution with which 
such altered masses must now-a-days be approached. We have done 
with the broad structural diagrams, accompanied by ‘theories of the 
earth, which had to serve as a basis for future observations, at a 
time when the labourers were few ; and Sir Archibald Geikie writes 
of the map of the lake district, “so rapid has the progress of certain 
branches of geology been since these sheets were published, that the 
map is even now susceptible of considerable improvement.” 
A strikingly new chapter, embodying results hitherto unpublished, 
or, perhaps, only hinted at in the annual reports of the Geological 
Survey, deals with “the Silurian Volcanoes of Ireland” (pp. 239-256). 
We note than an Arenig age is suggested for the crushed tuffs of 
eastern Tyrone, formerly regarded as ‘ Dalradian’; but “no recognis- 
able radiolaria have yet been detected” in the associated cherts. 
An interesting point in the description of the Old Red Sandstone 
eruptions is the occurrence of infillings of sandstone in the cavernous 
hollows of lavas poured out under water (pp. 283 and 333). In some 
cases, these sandstones are even stratified, reminding one of the 
material deposited in the interstices of a coral-reef. 
We are glad to note, on p. 346, the decided attitude taken up 
with regard to the correlation of the Dingle Beds. Irish geologists 
have, more or less, played with this important stratified series, usually 
referring it to the Silurian, although it clearly caps the Ludlow beds. 
Since Jukes led an attack upon the Devonian system as a whole, an 
attempt has been made to do without that system in Ireland, the 
Upper Old Red Sandstone being carried bodily up into the Carbonifer- 
ous, and the lower thrust down into the Silurian. No man living can 
speak with better authority on this point than Sir Archibald Geikie. 
The first volume closes with a superb series of full-page photo- 
graphs of the Carboniferous volcanic phenomena of Scotland. While 
these recall the work done by the Geological Survey of the United 
States, we can only regret that in our own islands their publication, 
on this ample scale, has been reserved for private enterprise. We 
cannot resist mentioning by name the view of the agglomerate of the 
Binn of Burntisland (p. 431), which equals the fine Cainozoic sections 
