90 Reports and Proceedings—Geological Society of London. 
and the “Lower Portlandian”’ are represented by integral portions 
of the Upper Kimmeridge, which are thus the “normal” form cor- 
responding to what the author calls the “ Boulognian episode.” 
The series in the Vale of Wardour has been made out pretty com- 
pletely. The Purbeck is separated by a band of clay from the Port- 
land, and is not amalgamated with it. The building-stones and 
flinty series are here seen again; and a fine freestone occurs at the 
base of the jatter. The representatives of the Portland sand were 
considered to be older than those of other districts. 
The relations of the Purbeck to the Portland rocks at Swindon 
were very carefully traced; and it is shown that, while the upper 
beds of the latter put on here some peculiar characters, the former 
lie on their worn edges. The upper beds of the Portland, which 
have been referred to the sand, correspond to the freestone and the 
base of the flinty series of the Vale of Wardour; hence the Purbecks 
of Swindon may be coeval with the upper beds of the Portland to 
the south. At the base of the great quarry and elsewhere in the 
neighbourhood are the “ Trigonia-beds;” beneath which is clay, 
hitherto mistaken for the Kimmeridge Clay ; and beneath this are the 
true Portland Sands, with an abundant fauna new to England. The 
limestones of Oxfordshire and Bucks were considered to represent the 
“« Trigonia-beds ” only ; and, as the Purbecks here lie for the most 
part conformably, it was suggested that they were formed ina lake 
at an earlier period than those at Swindon, which are of a more 
fluviatile character. 
Hence the Portland episode, considered as marine, was at an end 
in the north before it was half completed in the south. 
2. “On the Correlation of the Drift-deposits of the N.W. of 
England with those of the Midland and Eastern Counties.” By 
D. Mackintosh, Esq., F.G.S. 
The object of the author was not to dogmatize, but to present the 
subject in a concise form so as to stimulate to further research. 
His scheme of correlation was founded on the horizontal continuity 
of the deposits and their included erratics. He gave an account of 
his discovery of the continuous extension of the Upper Boulder-clay 
of Cheshire, above a great thickness of sand and gravel, as far as 
Berrington, south of Shrewsbury, and its appearance at intervals 
along the Severn valley to below Worcester, where it was probably 
represented by a bed with Malvern-hill boulders above shelly sand 
and gravel. He traced the great boulder-bearing clay and gravel 
around Wolverhampton eastward through Central England, to where 
it graduated into the chalky clay of Lincolnshire; and laid great 
stress on the commingling, at Wolverhampton, in this deposit, of 
erratics (chiefly granite and felstone) from the north with erratics 
(chiefly chalk-flints and gryphites) from the east. He described the 
clay and sand around Gainsborough, Retford, ete. He correlated 
the “carrion,” or Lower Boulder-clay of the Vale of York (containing 
Carboniferous, Jurassic, and granitic erratics), with the lower yellow- 
ish-brown clay of the Aire and Wharfe valleys and the plain of 
Craven. He likewise correlated patches of upper clay in the latter 
