376 
THE GEOLOGIST. 
common to other types. But eTen tliese characters were often needlessly- 
redundant, and several common to nearly allied groups might be cancelled. 
Having in this spirit examined an extensive series of lamellibranch shells, 
he found, in most cases, the hinge-characters among the more important 
residua ; and shortly afterwards, whilst determining some casts of fossils 
in which the hinge-teeth were the only generic characters seen, it occurred 
to him to write the teeth down in formula? like those used for the teeth of 
mammalia. Subsequent re-examination of specimens showed that in a 
large majority of cases these hinge-formulae were almost the only charac- 
ters with which the student need be troubled. 
On the Pennine Fault. By Mr. W. Bainbridge. — The Pennine fault 
in the Pennine chain, the backbone of England, commenced near Tindale 
Fell, in Cumberland, passed near Brough and Kirby Stephen, and near 
Kirby Lonsdale passed under the name of the Craven fault to the vale of 
the Wharfe, a distance of 130 miles. Professor Phillips had minutely de- 
scribed the Craven fault. The researches of Professor Sedgwick did not 
extend further north than Brough. The Craven and the Pennine faults 
were on a much grander scale than the Ninety Fathom Tynedale fault, 
for they had rent mountains asunder, and were, in fact, immense fractures 
or splits along a long line of stratification. The Pennine chain was ele- 
vated on an axis which is now represented b}^ the line of fault, but the true 
axis would probably reach further westward, and in time past the chain 
would have been higher than it is now. The slope to the western sea 
might have been as extensive as that now existing to the German Ocean. 
The author traced the igneous rock for nearly twenty miles along t1ie base 
of the carboniferous chain, showing it to be of varied form and elevation, 
spread out into fiat spaces, heaped up into lumpish hills, and rising to the 
skies in majestic graceful cones. The greenstone passed into slate of dif- 
fering hardness, and both were found indiscriminately along the line. 
There were no organic remains in either. The amorphous greenstone was 
a dull dark substance, often liable to decomposition, but often very com- 
pact. On the western sidj of Dufton Pike occurred beds of granite appa- 
rently in round or oval deposits, as also in the beck to the north, like that 
of Shap Fell. Smooth boulders of this granite and of basalt were dis- 
persed along the flanks of the chain northward. The granite on the Pike, 
and further south, contained mica. There were also veins or d3^kes across 
the line of greywacke, as at Gale, near Melmerby, containing felspar and 
Talc. There was no appearance of volcanic craters. Various conjectures 
might be hazarded as to the manner in which this mass of igneous matter 
was ejected. The wonderful forms of ]\Ierton and Dufton Pike seemed to 
prove that they began and completed their full stature after the elevation 
of the chain, for as fabrics like these could not at any subsequent period 
have been submitted to any serious aqueous disturbance, they seemed to 
indicate separate volcanic rests. There was no evidence in any part of the 
line of any extreme violence of explosion, and these pikes would probably 
not have survived in their present integrity any such fits of power. Their 
sides and summits must have been broken, and their contents reduced to 
the chaos apparent in other portions of the line. The growth of cones 
would require longer periods of time than that of pikes. It might appear 
to some an extravagant idea that the pikes had been burning mountains 
with regular volcanic rents ; but, like giant cones, they might, through a 
central channel, age after age, pour forth their masses of liquid matter, dif- 
fering in kind, but all successively hardening and consolidating the grow- 
ing mountains with one fiery garment laid on another, and that, further 
fastened by dykes and veins of interjected substances, as they appeared to 
