62 MES. JA>'E LO>G STAFF 0>' [vol. Ixxiii, 



referi'ed to it from the Silurian, prove to l)e a true member, its 

 origin must be more ancient. 



1 am greatly indebted to both Mr. K. Gr. Carruthers and 

 Mr. Peter Macnair for information resjjecting the horizons at 

 which the Scottish species occur. Their views agree in the 

 main with regard to the I'pper Limestone Series. But for the 

 Lower Lmiestone and Calciferous Sandstone Series I have been 

 guided bv Mr. Macnair, ^vhose recent extensive studies of the 

 stratigra])hy of these beds have led him to differ from the Geo- 

 logical Survey. He considers that there is no marked break 

 between the strata of the Calciferous Sandstone Series and the 

 succeeding LoAver Limestone Series, and refers to the latter all 

 the sedimentary rocks (including the Hollybush Limestone) that 

 occur above the Calciferous-Sandstone lavas of the West of 

 Scotland. 



Li Proc. Geol. Assoc, vol. xxvi, jDt. 3 (19L3 ; p. 179, he describes 

 the remarkably fine sections at Corrie Burn, Kilsyth (Stirlingshire), 

 and on p. 181 sums up thus : 



' The main points of difference between thi? reading of the succession and 

 that of the Geological Survey is that in the north of Ayrshire they take the 

 Docki-a Limestone as the Hurlet, the four succeeding limestones being respec- 

 tively the Blackball, Main Hosie. Mid Hosie, and Top Hosie. In Fife they 

 take the Seafield Limestone as the Hurlet ; this is mj Main Hosie. Tn the 

 Bilston Burn, Midlothian, they take the Gilmerton Limestone as the Hurlet, 

 whereas my Hurlet datum-line lies about 200 feet below the Gilmerton 

 Limestone.' 



Mr. Macnair regards the Doc-kra Limestone as underlying the 

 Hurlet, and as being equivalent to the Blaekbyre Limestone of 

 Kilsyth, Campsie. and Hurlet. In several conmiunications to the 

 Geological Society of Glasgow, published in their Transactions 

 during the years 1912-1(3, he supjDlies further details, and deals 

 Avith the correlation of these strata Avith those in Lanarkshire. 



Xo species of AcJisina and Aclisoicles have been recorded from 

 the Hurlet Limestone as here defined; this is not, however, 

 remarkable, since they are mostly small forms, and Mr. John 

 Smith 1 states that there is a great scarcity of fossils in this 

 stratum. 



The beds at Penton Linns (Dumfriesshire) have not been care- 

 fully zoned, therefore it is impossible to state the exact position of 

 those from which the gasteroj^ods here described are deri^-ed. The 

 undersides of" the slabs are crowded with Prodvctv.s longispiuKS 

 Sowerby, and there are numerous spines and fragments of the 

 brachiopods above. Dr. J. Home &. Dr. B. X. Peach - give a short 

 list of fossils from this locality in their account of the Canonbie 

 Coalfield, and state that they recall the assemblage of organic 

 remains of the Lower Limestone Series of Central Scotland. 



The exact relationship of the Scottish strata with the English 

 has not been thoroughly worked out, therefore the reference to 



' Ti-ans. Geol. Soc. Glasgow, vol. xlv, pt. ii (1911) p. 141. 

 2 Trans. Eoy. Soc. Edin. vol. xl (1903) p. 850. 



