British Association. 291 
Upper, Middle, and Lower Lias rise in succession from the shore 
into the cliff at a very low angle. Near the base of the series, and 
underlying the grey limestone beds containing Ammonites Bucklandi, 
Lima gigantea, and Gryphea incurva, is a series of light-coloured 
limestones and shales, which at Pinney Bay are well seen in the 
coast-section, and inland are equally well exposed in the quarries at 
Up-Lyme and near Axminster. These are the beds which were 
called ‘White Lias’ by Buckland, De la Beche, Conybeare, and 
others. Now, if that term was to be retained, we must give a more 
correct definition of it than hitherto, seeing that the series included 
light-coloured limestones belonging to two distinct zones of life. In 
the upper half we have 20 feet of limestones and shales, containing 
Ammonites planorbis and its varieties, Am. Johnstoni and Am. torus, 
with small Lima punctata; and in the lower beds of this upper half, 
Ostrea liassica, Modiola minima, Cidaris Edwardsu, Hemipedina 
Bechet, H. Bowerbankii, and, in fact, nearly all the species that cha- 
racterize the zone of Ammonites planorbis: with these mollusca are 
associated the bones of Ichthyosaurus and Plesiosaurus. 'The bottom 
bed of this zone consists of a light-coloured limestone, known as the 
‘ Anvil-ledge ;’ the marl resting upon it contains Ostrea lassica, 
Modiola minima, and Pullastra (Axinus) arenicola; the latter shell 
the author had not found in any higher bed, although it occurs 
abundantly in many of the beds of the lower half of the series. The 
‘ Anvil-bed’ may be therefore regarded as near the boundary between 
the under and upper divisions of the White Lias: below it are rubbly 
beds of limestone, with marly partings and concretionary bands, 
followed by laminated beds of fine cream-coloured limestone, splitting 
into thin layers, underlain by compact, concretionary, cream-coloured 
limestone, breaking up into cuboidal fragments when struck with 
the hammer: below these come nodular masses, forming a bed four 
feet thick, resting upon a band of the ‘Landscape-stone,’ or true 
‘Cotham._ marble,’ nine inches thick. The series of lmestones 
lying between ‘ Anvil-ledge’ and the ‘Cotham marble,’ inclusive, 
is from 18 to 20 feet thick. The fossils contained therein are chiefly 
small Conchifera in the state of moulds. Dr. Wright had collected 
Modiola, Lima, Cardium, Avicula, Axinus, Monotis, and Pecten, 
from the rubbly beds beneath ‘ Anvil-ledge,’ both at Up-Lyme and 
Pinney Bay; but the imperfect state of the moulds rendered the 
determination of the species impossible. The ‘ Cotham marble’ over- 
lies a greenish shale, resting upon another bed of white limestone. 
Below this is a nodular band, resting on a thick bed of hard grey 
shale; and underneath are greenish marls, overlying a thin band of 
light-coloured concretionary limestone, containing Estheria minuta. 
Below this characteristic band are six or eight beds of greenish 
marls and dark shales, containing very good specimens of Pecten 
Valoniensis, Cardium Rheticum, Avicula contorta, Axinus (Pul- 
lastra) arenicola, and Placunopsis. All the beds from the ‘Cotham 
marble’ downwards, to the east of the fault at Pinney Bay, must be 
followed out at low ebb during spring-tides. The same strata may 
be seen in the cliff at Charton, and at Culverhole Point, where the 
