80 Transactions. 
view a few others agree with Wahlenberg. In 1839 Sir Roderick 
Murchison described and figured in his Silurian System three 
species of Graptolites. He was of opinion that Graptolites show 
most affinity with the living Pennatulide. We are indebted to 
Professor Sedgwick for the first account of the rocks of the 
Moffat district. In his memoir, “On the Geological Structure 
and Relations of the Frontier Chain of South Scotland,” which 
was read at the British Association at Glasgow in 1850, he 
classed the rocks of the Southern Highlands into five successive 
formations. The oldest and lowest of these formations he called 
the Moffat group, embracing the greater part of the strata of the 
district. It was explained as “a great thickness of arenaceous 
rocks, in which pyritous and graptolitiferous schist abounds to 
such an extent that the arenaceous beds become sometimes sub- 
ordinate to it.” Inthe same year he also described and figured 
twelve species of Graptolites from the anthracitic shales (Upper 
Llandeilo) of Dumfriesshire. But there can be no doubt that 
the most valuable paper which has as yet been published upon 
the rocks of the Moffat district is the memoir of Professor 
Harkness “On the Silurians of Dumfries,” presented to the 
Geological Society of London in 1850. The author clearly 
adopted the view that the Graptolitic shales run in long lines 
among the unfossiliferous greywackes, and gave a short descrip- 
tion of several localities along the three parallel bands of Hart- 
fell, Frenchland, and Craigmichen. Following these bands for a 
number of miles through the district, he assumed their probable 
continuance from the one sea to the other, and seemed to consider 
that the great disturbances and upheavals which these rocks 
sustained were caused by three gigantic faults; but I find no proof 
of such faults running through the district. Sir Roderick Mur- 
chison, the same year, in his communication “On the Silurian 
Rocks of the South of Scotland,” made some important state- 
ments upon the strata of the district—some sections of which he 
had hastily examined under the guidance of Prof. Harkness— 
and expressed his willingness to accept Harkness’s theory of the 
identity of the strata forming the Graptolitic bands, but he pre- 
ferred to interpret their geographical position on the hypothesis 
of great folds, the upper arches of which had been denuded. 
This view is the one now generally accepted. The dark mud- 
formed shales that are associated with the Greywackes, and in some 
parts highly anthracitic, are evidently the remains of an ancient 
