708 ME. J. E. MAER AND DE. H. A. NICHOLSOIT 



the Lake-district, at least twenty-one also occur in the gregarius- 

 zone of Scotland, whilst only four species found in the latter aefa are 

 absent from the representative zones in the Lakes. The lithological 

 resemblances have been already commented upon, and there can be 

 no hesitation in correlating the Middle Skelgill Beds of the Lake- 

 district with the zone of Monograptus gregarius of Scotland. 



4. The succeeding subzone of Petalogra]ptus cometa is not differ- 

 entiated in our area. It appears to have thinned out ; it is partly 

 replaced by a mudstone band, or was formed contemporaneously with 

 the uppermost portion of the convolutits-'beds of the Lake-district; 

 the latter contain cometa rarely, and aU the forms found in the 

 cometa-zone are also found in our convolutus-zone, with the exception 

 of Rast rites ccqnllaris, Carr., which is recorded in Prof. Lap worth's 

 list at page 323 of his paper on the Moffat Series, but not in the 

 general list at page 328. 



5. The Cliyigani-band, which occurs at the base of the spinigerus- 

 zone in Scotland, may be compared with our Clingani-h&nd. Three 

 of the four forms mentioned by Prof. Lapworth are found also in 

 our band. 



The Birkhill zone of Monograptus spinigerus, on the whole, bears a 

 very striking resemblance to the zone containing this form in abun- 

 dance in the Lake-district. The CZm^/ani-band at Eldinhope E-uin 

 is succeeded by 6 feet of soft greenish-grey shales without Graptohtes. 

 At Skelgill it has above it the 4 feet 6 inches of blue mudstones 

 constituting the zone of Ampyx aloniensis. The many-coloured shales 

 above are quite comparable to those of the upper part of the spini- 

 gerus-zone in Scotland, even to the occurrence of the lozenge-shaped 

 patches on the rough surfaces of the harder beds. Of the Graptolites 

 from the spinig ems-zone of the Lake -district, ten out of sixteen are 

 found in the Bii'khiU Shales, or more than this if we count also 

 those of the C?w^am-band in our area, whilst three which occur in 

 Scotland have not jet been found in our zone. 



6. The abundance of Rastrites maximus in our uppermost zone of 

 the Skelgill Beds shows its relationship to the highest zone of the 

 Birkhill Shales. A fuller examination of the beds in the Spengill 

 section would almost certainly result in the discovery of a more 

 abundant fauna. 



It is noticeable that the maocimus-'hed^ occur in pairs in Scotland ; 

 and Prof. Lapworth states that at Craigmichan only one pair is 

 visible. We also have a pair of these beds separated by many feet 

 of mudstone. 



In this comparison we have not yet insisted upon what we con- 

 sider of far more importance than the occurrence of a certain 

 percentage of fossils common to the corresponding zones (for the 

 percentages would certainly be considerably increased after further 

 work), namely, the great abundance of the characteristic forms of the 

 different zones in the corresponding order, AVe find : — 



