516 Revieics — The Surrey Memoir on the ScMuli Uplands. 



in the body of tlie work, the writer has done all that can be 

 reasonably expected of him. Any further reference is uncalled for. 

 Such vain repetition can only add unnecessarily to the amount of 

 the printer's bill, and increase, what is already amply sufficient fur 

 scientific purposes, the vanity of the species-maker himself. 



In their work among the rocks of the Central Belt, already noticed, 

 the Survey officers wei'e mapping ground where the typical sections 

 had already been worked out and the general sequence ascertained. 

 The aim and end of their researches was that of interpreting tlie 

 complicated structure of the whole belt in terras of the part. But 

 in their work in the Northern Belt, which ranges from Dunbar, 

 through the Leadhills to Loch E.yan, they were dealing with 

 a country of which little was known and less published. It is true 

 that it was already acknowledged that in this belt the greywacke 

 type of sedimentation had descended well into the heart of the 

 Oaradoc (Hartfell) formation, so that all that remained of the black- 

 shale type of the Moffat Series was a degenerate Glenkiln-Hartfell 

 group of the characteristic Moffat facies and tenuity, ranging 

 upwards no higher than the base of the Upper HartfeU. It was 

 also known that this Moffat - like band, although rich in 

 graptolites, is exceedingly difficult of unravelment, not only owing 

 to the incoming of arenaceous and ashy members among the black 

 shales, but also because of the unusually excessive wrinkling and 

 puckering, dislocation and alteration, which the rocks of the country 

 have undergone. 



It is perhaps in this Northern Belt that the discoveries of the 

 Survey officers have been most brilliant, and the value of the zonal 

 methods most triumphantly demonstrated by them, but the great 

 difficulty of their task will be appreciated on a study of the 

 numerous sketch-maps and sections given in the chapters which 

 illustrate their researches into the remarkably complicated structure 

 of this region. They show that the 30 feet or so of Barren 

 mudstones of Upper Hartfell age in the Moffat district have here 

 become transformed into a massive series of grey and blue 

 micaceous flags and shales (Lowther or Heriot Shales), with 

 conglomerates and limestone bands. The Survey officers have proved 

 for the first time that to this horizon belong the famous limestone 

 beds of Wrae Mill, which they have ascertained are associated with 

 a remarkable contemporaneous series of volcanic rocks, felsitic lavas 

 and tuffs, apparently representatives of the rhyolitic lavas and ashes 

 of Snowdon. 



The Glenkiln - Lower Hartfell Series presents marked and often 

 rapid lithological variations. The Lower Hartfell graptolitic black 

 shales with flinty bands pass laterally into grey wackes and calcareous 

 conglomerates, occasionally rich in fossils (Dunterclengh Beds), and 

 often with local unconformities presenting many peculiar features. 

 Similarly, the G-lenkiln graptolitic shales and cherty beds pass 

 lateralljr into massive grits, grey wackes, and shales some 1,^00 feet 

 in vertical extent. 



From underneath the Glenkiln Beds rises again and again the 



