J. G. Goodchikl — Beutozoic Rocks of North Britain. 591 



should read " as far as Scabbacombe Head, east of Dartmouth." He 

 asserts, moreover, that " they exist also on the north of the Devonian 

 basin." There they are represented, no doubt, and in 1889 * 

 I tentatively classed them with the Foreland grits as Gedinnien 

 but there is no distinct group of similar character in North Devon 

 or West Somerset. 



V. — The Older Deutozoic Rocks of North Britain. 



By J. G. GooDCHiLD, F.G.S., of the Geological Survey, 



Curator of the Collections of the Geological Survey of Scotland in the Eoyal 



Scottish Museum. 



IT appears to be a common belief that there are two Old Red 

 Sandstones in Scotland, and only two, which are referred to 

 respectively as the Upper and the Lower. It is generally recognised 

 that neither of these can be paralleled with any one of the subdivisions 

 of the Devonian Rocks, properly so-called ; though the fact that 

 the Scottish rocks in question occupy a stratigraphical position 

 somewhere between the top of the Silurian Rocks and the base of 

 the Carboniferous System places their Devonian age beyond the 

 possibility of a doubt. The Upper Old Red is considered by most 

 persons to graduate upwards into the Carboniferous Rocks, which, 

 by the way, is by no means universally the case. It is also stated, 

 with equal confidence, and with as little regai'd to the facts, that 

 the Lower Old Red Sandstone graduates downward into the Silurian 

 Rocks, which it certainly does not, as will be shown more fully 

 in another part of this paper. Furthermore, it is still commonly 

 believed that bands yielding Silurian graptolites alternate with the 

 base of the Lower Old Red Sandstone, and that Lower Carboniferous 

 fossils occur in bands of rock interstratified with true Upper Old 

 Red Sandstone. Both of these ideas are well known to have been 

 due to errors of observation ; yet the statements in question, having 

 found their way into the papers set by examiners, seem destined 

 to die a hai"d death, and therefore need to be contradicted. 



The errors mentioned are by no means the only ones relating 

 to the rocks of Devonian age in North Britain. Therefore, as no 

 one else who is fairly well acquainted with these rocks has yet 

 come forward with the object of stating the actual facts, I propose 

 to take advantage of the present opportunity (when I am about 

 to present some new suggestions regarding the age of some volcanic 

 rocks on the northern margin of the Lake District) to give a con- 

 spectus of what is at present known about the Scottish rocks of 

 Devonian age. 



As much of the evidence bearing upon this subject is necessarily 

 of a palasontological nature, I gladly avail myself of some of the 

 published results of the important work done in this direction by 

 Dr. Traquair, and accordingly give here lists of such fossils as 

 serve to characterise the several horizons referred to. A list of 



^ Proc. Somerset Arch, and Nat. Hist. Soc, vol. xv, pt. 2, Table of Classification, 

 in which * Gedinnien ' is placed in line with Lynton Beds through a printer's error. 



DECADE V. — VOL. I. NO. XII. 35 



