Mr. N. Wood on the Geology of Northumberland, S^c. 327 



pretty nearly the basset face of the other. In the Alston Moor district 

 we find a series of seven beds of Limestone, alternating with Hazel and 

 Plate, below the great Limestone, when we reach a bed of Basalt, called 

 the " Whin Sill." I am aware, that by some, the apparently detached 

 masses of Basalt, which cap several of the eminences in Northumber- 

 land, have been considered as overlying masses. On a more attentive 

 examination, however, and particularly in I'eference to the connection 

 of this Basalt with the beds previously traced, and also with the inferior 

 Limestone beds, it will, I trust, appear, not only that the Basalt of the 

 Lead Measures, commonly called the Whin Sill, ought to be considered 

 as a stratum, keeping nearly a determinate place in the series, but that 

 the whole of the apparently detached masses of Basalt, in the county 

 (except those occurring in the shape of Whin Dykes), are attributable to 

 this bed of Basalt. 



The escarpment at Croglin exhibits four beds of Limestone above 

 the Basalt, all of which are below the great Limestone. How many 

 more there may be cannot be determined. Along the face of the hills, 

 above the plain, the Basalt keeps nearly in the same position to Cumrew, 

 when we lose it amongst the Slip Dykes near Talkin. Following the 

 direction of the beds north-eastward, we find the Basalt again bassetting 

 out near Temmon, and adjoining the turnpike-road between that place 

 and Gap-shields. Crossing the vale of the Tippald, we again find it bas- 

 setting out on the east bank at Wall Town Crag. From thence to Walwick, 

 it forms a series of bold and pointed eminences, nearly along the line of 

 the Roman Wall ; we then lose it amongst the debris on the west bank 

 of the North Tyne ; but, crossing the vale, find it again at Barresford, 

 from whence it stretches away towards Bavington and Kirkwhelping- 

 ton. From this place, for a considerable distance eastward, I have not 

 had an opportunity of tracing it ; but it probably keeps on the south 

 side of the Simonside hills, and east of Rothbury, as we find, to the west 

 of these localities, the Limestone beds, which in the other parts of its 

 course underlie the Basalt. Further to the north east we find it skirt- 

 ing the east side of the moors above Alnwick, where it is quarried at 

 Greenfield. Passing the denudation of the Aln it is exposed at RatchiiF 



