364 



succeeded, in an ascending order, first by amagnesian conglomerate, 

 quite identical with that which overlies the south-western coal-fields ; 

 then by magnesian limestone; afterwards by red marl with gypsum and 

 bands of carbonate of zinc ; and, lastly, by the new red sandstone of 

 St. Bee's Head. The identity of different parts of this succession 

 with the groups overlying the carboniferous system of Yorkshire and 

 Durham, is described in detail ; and by further comparisons we learn, 

 that the great member of the red sandstone, described in this and 

 former memoirs by the same author, as the equivalent of the rothe- 

 todte-liegende and the Grlsde Vosges, is entirely wanting in the south- 

 west of England, the conglomerates of which (near Exeter and the 

 Mendip Hills) stand in the place of the second member of this series, 

 as existing in countries where the system is fully developed. 



The concluding part of this valuable memoir, is occupied with a 

 brief reconsideration of the red sandstone formations of Scotland ; and 

 the author confirms the views, published by him and myself, respecting 

 the great antiquity of the vast range of red sandstone and conglome- 

 rate surrounding the highland regions of Scotland — by pointing out 

 the continuity and mineral identity of the whole range, the south- 

 eastern limb of which has been shown by Dr. Fleming to pass under 

 the coal-fields of Fifeshire — by stating that it has not a single fossil 

 in common with the magnesian limestone series — by instancing a 

 case where a newer red sandstone is found overlying the old red in a 

 transverse position : Finally, from a consideration of the coast 

 sections of Arran, the nature of the carboniferous series of Scotland, 

 and the apparent passage from the coal measures of the North of 

 England into the lower part of the new red sandstone, he concludes, 

 that the succession of the lower, secondary formations of the northern 

 parts of Great Britain, lends some support to the classification adopted 

 in Germany, by which the carboniferous series is placed subordinate 

 to a vast formation of red sandstone. 



Mr. W. Hutton has communicated an elaborate memoir on the 

 Whin Sill of Northumberland, which he conceives to have been one of 

 the oldest basaltic eruptions of that neighbourhood, and to have been 

 poured forth at a period, when a great number of the strata of the 

 metalliferous series were not in existence, these having been subse- 

 quently deposited on the unequal surface of the basalt. 



Professor Sedgwick, many years ago, arrived at a different con- 

 clusion. From repeated and careful examination of the southern 

 branch of this great mass in High Teesdale, he ascertained it to have 

 there a wedge-shaped form — to have acted mechanically and chemi- 

 cally upon the strata above and below — and to be interstratified with 

 different beds of limestone and sandstone ;— and thence he inferred, 

 that the igneous matter must have been injected laterally between 

 those beds subsequently to their consolidation. He had previously 

 given a masterly view of the great trap dyke of Bolam, which 

 pointing to High Teesdale as the seat of its origin, traverses the 

 southern coal measures of Durham, and seeming to plunge beneath 

 the magnesian limestone, re-appears and continues its course even 

 through the lias and inferior oolite of the Yorkshire Moorlands. 



