GEOLOGY FOR CYCLISTS 
233 
types were much simpler and yet more comprehensive, in that 
they combined characters which in later ages became differen- 
tiated so as to occur in distinct animals. Thus Ictitherium 
combined features peculiar to the living hyaena and civet, and 
Hyanarctos, those of the hyaena and bear. In the case of several 
genera, almost perfect genealogies have been drawn up. The 
horse, for instance, is known only in the more modern deposits, 
but its five-toed ancestors existed in the earliest Tertiary strata. 
By gradually losing first one and then another toe, the foot has 
been reduced to one, the single hoof of each foot being the 
middle or second finger, while corresponding changes occurred 
in the structure of other bones and of the teeth. 
The whole geological series closes with Man. In thus 
sketching the history of life in the past history of the world, 
three features stand out prominently : first, that the progression 
has been always steadily from lower to higher types ; secondly, 
the earlier forms of life were “ embryonic ” in character when 
adult, i.e., the full-grown animals presented characters now 
found only in the transient stages of higher types ; thirdly, there 
is the survival of a few ancient forms now isolated and without 
living kin, such as Nautilus, Lingula, Trigonia, the Port Jackson 
shark, and the mudfish, among animals, and the Horsetails 
( Equisdum ), and Club-mosses [Lycopodium), among plants. The 
two principles, therefore, to be deduced from the study of the 
biology of the past are evolution and persistence of type, not without, 
in some cases, degradation as well. 
There are many convenient centres from which the cyclist 
can make tours to examine the quarries and other places of 
geological interest. Thus at Ludlow he can search for fossils in 
the Silurian, or round Plymouth for the corals characteristic of 
the Devonian. At Buxton the Carboniferous Limestone can be 
studied, and the formation of caves by subterranean river action ; 
from Scarborough many interesting excursions can be made, 
such as to Whitby for the Lias with its ammonites, to Malton for 
a magnificent coral reef, or to Flamborough Head for red chalk ; 
from Cheltenham the Inferior Oolite of Leckhampton Hill, and 
the Liassic Marlstone of the Severn valley can be examined ; 
and from Ipswich the Pliocene Red and White Crags of 
Ramsholt, Felixstowe, Walton-on-the-Naze, and Trimley. 
If a cyclist will first make some preliminary study of the 
subject, and “ read up ” the geology of the district he purposes 
visiting, for which purpose he will find Mr. Harrison’s “ Geology 
of the Counties of England,” published by Kelly and Co., of 
great assistance, he will not only find the scenery an object of 
attraction, but every valley and hill will be endowed with a new 
interest, and the embedded life will reveal a new world to him ; 
and while thus widening his view of Creation to an indefinite 
extent, he will discover a reaction taking place in his own mind, 
which will become filled with admiration, if not with awe, at 
the mighty Power which exists behind and above the works 
of Nature. G. Henslow. 
