420 Geological Society : — 



The Caithness breccias were perhaps more analogous to the stone- 

 rivers of the Falkland Islands, but they also indicate a rather low 

 temperature ; while the Flysch-breccias land us in the following 

 dilemma, namely, that either similar temperatures existed in Switzer- 

 land, and that there was also an important highland district, of 

 which no remnant can be found, within a short distance of the 

 breccia-beds ; or they must be the product of a range not inferior 

 to the present Alps, which also has completely disappeared, and 

 would be (for reasons given) very difficult to locate. But, even in 

 the latter case, we seem forced to admit that a temperature if not 

 lower, at any rate not higher than the present, prevailed in Central 

 Europe late in the Eocene Period. 



February 26th.— Prof. Charles Lapworth, LL.D., F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. ' On some Gaps in the Lias.' By Edwin A. Walford, Esq., F.G.S. 



The author's endeavour is to prove gaps in the stratigraphical 

 succession of the Lias, involving the removal of zones or parts of 

 zones, and also to prove palasontological gaps by the abrupt appear- 

 ance of many new genera of mollusca. 



The Middle Liassic ferruginous limestone of the zone of Ammonites 

 spinatus he states to be mainly made up of a kind of crinoid (ferro- 

 crinoid). The zone may be divided into 



2. The Ferrocrinoid bank — upper. .°>0 feet. 

 1. The Spirifer-oxygona beds —lower. 20 feet. 



The upper division varies from 30 feet at an altitude of 700 feet to 

 feet at the altitude of 350 feet on the edges of the Cherwell Vale, 

 owing to waste by drainage. The upper zone is of great thickness 

 and importance in Oxfordshire and Yorkshire (Cleveland), but almost 

 absent in Dorset, Somerset, and Gloucestershire, where the fauna of 

 the lower Spirifer-o.vygona beds prevails. The ironstone is thickest 

 towards the escarpment on the west of the Cherwell Vale ; on the 

 east side of the vale, it loses both in type and importance. At 

 Bloxham a course of ferruginous limestone is made up of stems of 

 the ferrocrinoid in great part, but near the top it becomes a pink 

 compact limestone, full of fossils of the zone of Ammonites communis: 

 the intermediate transition-bed and zone of Ammonites serpentinus 

 having been removed by inter-waste rather than by contemporaneous 

 erosion. 



A transition-bed between the Middle and Upper Lias shows 

 a great incoming of new forms. They are no doubt developed 

 outside lines of known strata. 



A third gap, measured by the occurrence of a thin bed of 

 Pentacrinite-limestone, is in the zone of Ammonites communis. 



The ' spinatus-ironstovLQ ' is believed to lose in thickness on the 

 side of a divide away from the main west-to-east dip. On the North- 

 amptonshire side of the Cherwell, where the slope is to the west, 

 and hence opposite to the general dip, the beds are thin, although 

 the argillaceous beds are better preserved. 



