HISTORY OF RESEARCH. 



Hopkinson's third paper contained a description of several 

 now species from the South of Scotland. 



The first two, according to him, do not belong to the 

 Graptolitidse proper, but are nearly allied forms. Order, 

 Hydroida, Sub-order, Athecata ? Family, Corynidoe. — (1) 

 Gorynoides gracilis, (2) Dendrograptus ramulus. Sub-order, 

 Monoprionidae, (3) Gr. attenuatus, (4) Gr. acutus, (5) Diplogr. 

 penna, (7) D. pinguis, (8) I), fimbriatus, ('•>) JJ. Hincksi, 

 (10) Dicranog. rectus. 



Hopkinson, in discussing the age of the Moffat shales, acknowledges it as 

 probable that but one band of black graptolitic shale runs through the Llandeilo 

 rocks of the South of Scotland, there being in this band " several distinct zones, 

 by a different assemblage of i'ossils, but with many species in 



1872. 

 Hopkinson, 

 " On some Species of 

 Graptolites from the 

 South of Scotland," 

 ' Geol. Mag.,' vol. ix. 



Rhabdophora, Fam. 

 Etheridgii, (6) D. 



each marked 

 common." 



1872. 



Nicholson, 



On the Migrations of 



the Graptolites," 



' Quart. Journ. Geol. 



Soc.,' vol. xxviii. 



A paper by Nicholson in this year " On the Migrations of 

 the Graptolites " is mentioned here because of its historical 

 value. His conclusions may be thus summarised : — The 

 Skiddaw fauna was the oldest in Britain and migrated into 

 Wales, Ireland, and America, four species only migrating 

 northward into the Moffat area. The South of Scotland 

 became a second centre of dispersion at the end of the Upper Llandeilo period, 

 one migration proceeding southwards into the Lake district, founding the fauna of 

 the Coniston group, and another going westward through Ireland to America and 

 originating the fauna of the Hudson River group and that of the Utica Slates, 

 while a third travelled in a south-east direction into the Silurian seas of Saxony 

 and Bohemia. 



In a short note published in the ' Geological Magazine,' 

 towards the end of 1872, Lap worth summarised his views on 

 the age and stratigraphical relations of the Moffat Shales, as 

 partly given in a paper read by him at the beginning of the 

 year before the Geological Society of Glasgow (subsequently 

 published, with additions, in the ' Transactions ' of that 

 Society, vol. iv, p. 1G4). He points out that there are three 

 main divisions, " lithologically and palasontologically separ- 

 able " ; which " naturally subdivide into several distinct zones, 

 each characterised either by the exclusive possession of some well-marked species, 

 or by the constant possession of some peculiar group of species." 



18 72 During the same year Nicholson published the first part 



Nicholson, (t he " General Introduction ") of his ' Monograph of British 



' A Monograph of the Graptolitidse,' a work unfortunately never completed. It is 



British G-raptohtidae. f especial historical interest, as giving a complete summary 



1872. 



Lapworth, 



" Note on the Results 



of some Eecent 

 Researches among the 



Graptolitic Black 



Shales of the South of 



Scotland," 'Geol. Mag.,' 



vol. ix. 



