to been
considering are wholly unrepresented at the present day, and
do not even pass upwards into the Tertiary period. It may be
mentioned, however, that the Oolitic deposits have also yielded
the remains of Reptiles belonging to three of the existing orders
of the class-namely, the Lizards (_Lacertilia_), the Turtles
(_Chelonia_), and the Crocodiles (_Crocodilia_). The Lizards
occur both in the marine strata of the Middle Oolites and also
in the fresh-water beds of the Purbeck series; and they are of
such a nature that their affinities with the typical Lacertilians
of the present day cannot be disputed. The Chelonians, up to
this point only known by the doubtful evidence of footprints
in the Permian and Triassic sandstones, are here represented by
unquestionable remains, indicating the existence of marine Turtles
(the _Chelone planiceps_ of the Portland Stone). No remains of
Serpents (_Ophidians_) have as yet been detected in the Jurassic;
but strata of this age have yielded the remains of numerous
_Crocodilians_, which probably inhabited the sea. The most important
member of this group is _Teleosaurus_, which attained a length of
over thirty feet, and is in some respects allied to the living
Gavials of India.

[Illustration: Fig. 181.--_Archoeopteryx macrura_, showing tail
and tail-feathers, with detached bones. Reduced. From the
Lithographic Slate of Solenhofen.]

[Illustration: Fig. 182.--Restoration of _Archoeopteryx macrura_.
(After Owen.)]

The great class of the Birds, as we have seen, is represented
in rocks earlier than the Oolites simply by the not absolutely
certain evidence of the three-toed footprints of the Connecticut
Trias. In the Lithographic Slate of Solenhofen (Middle Oolite),
there has been discovered, however, the at present unique skeleton
of a Bird well known under the name of the _Archoeopteryx macrura_
(figs. 181, 182). The only known specimen--now in the British
Museum--unfortunately does not exhibit the skull; but the
fine-grained matrix has preserved a number of the other bones
of the skeleton, along with the impressions of the tail and wing
feathers. From these remains we know that _Archoeopteryx_ differed
in some remarkable peculiarities of its structure from all existing
members of the class of Birds. This extraordinary Bird (fig.
182) appears to have been about as big as a Rook--the tail being
long and extremely slender, and composed of separate vertebrae,
each of which supports