LOWER LIAS.--For the most part this formation spreads over the portion of the country on the north-east, east, south-east, south and south-west of Warwick. A remarkably fine section is exposed in the railway cutting near Harbury Station. This portion of the series is also largely quarried at Rugby, and in other places south and south-east of Stratford. The strata consist of beds of blue clay or shale interstratified with beds of blue rubbly and argillaceous limestone, much quarried for hydraulic lime. One good section of the lime-yielding beds occurs at Messrs. Greaves and Lakin’s Quarries at Stockton and Harbury. The lowest zones of the Lias are largely quarried at Wilmcote, and may be seen at the remarkable outlier of Brown’s Wood, near Henley-in-Arden, and at another (Copt Heath), near Knowle. These two last are of special interest, because they shew the lowest beds of the Lias (in connection with and passing into the Rhætics,) resting immediately upon the New Red Marls. The thickness of the Lower Lias in the county is above 600 feet; but only the inferior zones of _Ammonites angulatus_ and _A. planorbis_ are laid open to any great extent. The best sections of the _Lima_ beds (_A. angulatus_ zone) occur in the railway cutting at Harbury, Stockton lime quarries, and the extensive quarries at Newbold near Rugby. Fossils are not very numerous, but the following occur:--_Gryphea incurva_, _Rhynchonella variabilis_, _Ammonites angulatus_, _Pecten_, various species, _Lima gigantea_, and bones and teeth of _Plesiosaurus_ and _Ichthyosaurus_. Fish are comparatively rare, two or three only were found at Harbury and a very few near Rugby.
The higher ground round Wilmcote and Binton is also capped by these Lima beds; but the district is more or less affected by small faults, so that certain beds in one contiguous quarry are absent in another. The lower limestones (insect beds) are largely worked in this locality, and are of much economical value. With the exception of remains of insects and fragments of plants, the fossils are entirely marine, _Ammonites planorbis_ and _A. Johnstoni_, being abundant and characteristic. Crustacea belonging to the genera _Astacus_ and _Eryon_, the latter of great size are not unfrequently met with. Small fishes, _Pholidophorus Stricklandi_, and the larger _Dapedium_ and _Tetragonolepis_ more rarely occur. A fine example of the latter is preserved in the Warwick Museum. The large _Enaliosaurians_ are well represented by some fine specimens of _Ichthyosaurus_ and _Plesiosaurus_; the _P. megacephalus_ in the Museum at Warwick being nearly entire, measuring 14 feet 4 inches in length. Large masses of driftwood and a few fronds of ferns are sometimes met with. But perhaps the most interesting and remarkable fossils are the insects. Twenty-four families and genera were determined more than twenty years ago, since which time many important additions have been made. The _Coleoptera_ and _Neuroptera_ are most numerous. Small beetles are not unfrequently found entire. Among these may be noted the families _Buprestidæ_, _Elateridæ_, _Carabidæ_, and others.