338 
THE GEOLOGIST. 
exliumc tho relics of its once tectniag population from their stony 
tomb. If, liowever, the geologist has this advantage over the naturalist, 
he has often only the skeletons, or, indeed, but mere imperfect 
remnants by which to decipher and restore the forms and attributes 
of ancient creatures ; while the naturalist, though he cannot walk 
beneath the waves, still can, by the aid of the dredge, collect the 
animals in their full symmetry and beauty. The student of the pre- 
adamitic earth has, however, a no less delightful task, and the very 
labour and the difficulty of the restorations bring their own reward, in 
making known to others the marvellous works of God in the earliest 
ages. In this spirit let us review the history of the Lias, and it shall 
tell its own storj'- as we proceed. 
The Lias has a very extensive range in Gloucestershire, and consists, 
for the most part, of alternating beds of clays, limestones, and shales, and 
towards the middle includes a thick and important mass of sandstone. 
Lithologically it presents a very different aspect from the Oolites above 
it, as the student cannot fail to observe. It contains a great 
abundance and variety of organic remains, the greater part of which 
are peculiar, some being limited to particular zones (especially the 
Ammonites), and others occurring indiscriminately throughout the 
formation, which presents, as a whole, a great uniformity of structure 
and details, and consequentlj'^ can be most readily recognised in different 
and distant localities, even without the aid of characteristic fossils. In 
general, no cautious geologist would venture to determine a rock by 
mere similarity of lithological character, the only safe rule to distinguish 
the same formation in another country being by its relative position 
with regard to other superior or inferior rocks, and its organic remains. 
The Lias is essentially a muddy deposit, and from the regular layers of 
which it is made up, and which may be seen even iu a small section, the 
term Lias appears to have been derived. In Gloucestershire, it is 
divided into upper, middle, and lowei', distinguishable from each other 
by their order of superposition and their peculiar fossils. The upper and 
middle divisions form the base of the Cotswold Hills, and their 
detached outliers ; while the lower divisio;], here and there ^constituting 
lesser elevations, for the most part spreads over the vales of Gloucester 
and Berkeley, and occupies tho whole of the comparatively level tract 
between the Cotswold Hills on the cast and the lied Marl on the west, 
its narrowest point being tho more central region in the neighbourhood 
