Reviews—Prof. Huil’s Geological History. 173 
we are helped by facts gained by deep borings, by the facts of 
paleontological distribution, and by the nature of earth-movements 
of preceding periods. 
Even if we pass over the extreme difficulty exhibited by the nature 
of the case in the Archean and Lower Paleozoic ages, it is difficult 
to see why the author has said so very little about his favourite 
Devonian period, so little that even the customary “Position of 
Sea and Land during the Period” has been omitted. Turning 
again to the @arboniterons period, Englishmen reading an English 
book would have liked some reference, not only to the iNeTantioNes 
summary of the arguments for which is given, but to the borders of 
the continent, whatever it was, on whose edges the deposits so 
important to our industries were made, and some of whose shore 
lines have been so well worked out in England. The notice of the 
wide spread of shells and plants in this period i is interesting, but the 
untrained reader needs to be shown the bearing of this in the 
increased complexity of the barrier system which ouides distribution, 
introduced by the development of earth-movement as time went on. 
The author again has been one of the chief to insist on great crust 
movements some time after the Carboniferous period ; should he not 
have shown us that the development of the Pendle and London 
ridge, and other HE. and W. ranges, and of the Pennine and other N. 
and §. ranges, must have had some influence on the geography of 
the succeeding Permian or, at latest, the Triassic periods? As we 
reach later times, the geography is better worked out, but even 
here we are not definitely told that while conformable strata furnish 
the history of submersion, unconformabilities are no less valuable as 
giving evidence of land surfaces, and, by telling us of movement and 
mountain building, show us in what direction to look for shore lines ; 
nor do we think the term “conformable hiatus” has any very 
decided advantage over the older one of deceptive unconformity. 
Side by side with rock history we are given an account of the 
fossils of each formation. The technical student has no need of such 
lists, and of what use can they be to the general reader? The author, 
rather late in the work, sets himself an example when he gives a 
partial sketch of the evolution in the ancestry of the Horse. Ought 
he not to have shown that the same can be done for some other 
Mammalia, and to have indicated, throughout the Tertiary period, 
a tendency to advance from generalized to specialized forms of life ? 
The Dinosaurs and Birds have their proper share of attention in the 
Mesozoic rocks, but we cannot help thinking that a few words of 
explanation on the zoological position and affinities of the rest of the 
Reptiles, of the Amphibians, and the Fish would have been more 
useful than clouds of names ; nor do we think that the bald statement 
that a species of Ceratodus survives in Australian rivers is enough to 
make of a most significant fact. Could not the author have helped 
the reader by giving him an inkling as to what a heterocercal tail 
really meant, and particularly in alluding to the embryonic fish types 
of the Devonian period? The possibility of an explanation of the 
sudden appearance of so many forms of life in the Cambrian period 
