376 



THE GEOLOGIST. 



common to other types. But even these 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-formula? 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 by 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 the base 

 of the carboniferous chain, showing it to be of varied form and elevation, 

 spread out into flat 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 side 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 Snap 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 dykes across 

 the line of greywacke, as at G-ale, 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 Merton 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 



