C, L1PW0RTH ON THE MOFEAT SERIES. 285 



Shales, and of these there is here exposed the most complete section 

 known io me as existing on the southern side of this band ; and 

 the proof it affords that the ArdweU beds stand in the same relation- 

 ship to the Moffat Series as all the greywackes to the northward is 

 indubitable and overwhelming. 



Two small arches at the base of the group bring up the soft shivery 

 shales of the D.-acuminatus band, with their characteristic fossils. 

 These are followed by a great thickness of hard flaggy beds, 

 showing in their upper portions the variegated mudstones of the M.~ 

 gregarius zone, and yielding in abundance Diplograptus vesiculosus, 

 Climacograptus rectangularis (M'Coy), and, higher up, Monograptus 

 gregarius (Lapw.), Rastrites peregrinus (Earr.), &c. 



The lowest zones of the Upper Birkhill Shales are much broken ; 

 but the majority of their characteristic fossils may be collected. 



The highest or R.-maximus division can be identified at a glance ; 

 the grey shales with black bands, the yellow and white clay seams, 

 &c. are clearly shown and perfectly unaltered. The commonest 

 fossils are Rastrites maximus (Carr.), Monograptus Halli (Barr.), M. 

 Hisingeri (Carr.), and M. runcinatus, Lapw. 



These strata are separated from the greywackes to the south by a 

 few feet of shales and flaggy beds as in other localities, all the strata 

 being inverted, and dipping to the north-west at an angle of 

 about 45°. 



On the opposite margin of the band, a few feet of the lowest 

 portion of the grey group are visible in a small projection at the 

 junction of the two streams. They swarm with beautifully pre- 

 served examples of Diplograptus cometa (Gein.), Monograptus lepto- 

 iheca (Lapw.), &c. To the south-east these beds are faulted against 

 the Hartfell Shales ; to the north-west the remainder of the suc- 

 cession is obscured by turf and heather. 



DuffTcinnel. — Beyond Belcraig the Silurian rocks are buried be- 

 neath the coarse Permian deposits of the vale of the Annan. They 

 again emerge in rolling ground near Baehills, and numerous in- 

 different sections are apparent in the banks of the various mountain- 

 streams. The most important is that of Duffkinnel, where dis- 

 located and altered Birkhill Shales swarm with beautifully preserved 

 Graptolites. 



iv. Glenkiln Bum (PI. XIII. Plans P, G). — Continuing our course 

 in the same general direction to the south-west, we finally reach the 

 notable sections of Glenkiln Burn. The dark shales are here ex- 

 posed in two distinct sections, which are divided from each other 

 by a band of greywackes a quarter of a mile in width. 



Lower Exposure (fig. 19). — The first of these sections occurs at 

 the spot called Black Linn. With the exception of one small group 

 of strata, all the beds exhibited belong to the lowest division of the 

 Moffat Series. Of the beds of this division, indeed, this may be 

 regarded as the typical exposure. They are here clearly separated 

 from those of the succeeding divisions, and at the same time swarm 

 abundantly with their characteristic fossils. Hence their special 

 title of the Glenkiln Shales. 



