200 Mr. C. Lapworth on the Geological 



at Tosterup in Scania, in Westrogothia, and in the schists 

 of Dalarne — in Thuringia, Bohemia, the Eastern Alps, France, 

 and Spain. 



13. Zone of Monograptns spinigerus, Nich. (Sedgwicki, 

 Portlock). — This zone overlies the former throughout the 

 greater part of its extended geographical range ; and the 

 fossils of both have been intermingled in published lists. 

 It is distinguished from the M.-gregarius zone by the pre- 

 sence of M. spinigerus, Nich., M. Hisingeri, Carr., M. inter- 

 medins, Carr., M. argutus, Lapw., Diplograptus comet a, 

 Geinitz, D. palmeus, Barr., &c. It is recognizable in the 

 Moffat and Girvan areas, in Ireland at Pomeroy, in the 

 Coniston Mudstones, at the Devil's Bridge, Cwn Symlog, 

 &c. in Mid Wales, at Kongslena in Westrogothia, &c. 



14. Zone of Kastrites maximus, Carr. — In many respects 

 this must be regarded as the zone of transition into the suc- 

 ceeding formation. Its fauna is essentially a compound of 

 that characteristic of the more strikingly separated beds above 

 and below. It ought in all probability to be regarded as 

 forming the base of the Tarannon group. Its most striking 

 species are Rastrites maximus, Carr., and Monograptns cras- 

 sus, Lapw., the first of the forms of the type M. priodon, 

 Broun. The zone has a wide range in South Scotland, and 

 has been doubtfully recognized in Mid Wales, Scania, and 

 Dalarne. 



15. Zone of Monograptus exiguus, Nicholson. — This is the 

 typical Tarannon or Gala zone of Britain. The thin grapto- 

 litiferous seams found occasionally in the thick zones of flag- 

 stones and purple-and-green shales of this formation are often 

 matted with entangled groups of the characteristic form of the 

 zone. M. galaensis, Lapw., M. crispus, Lapw., M. turri- 

 culatus, Barr., M. Salteri, Lapw., are generally peculiar. 

 The remainder are survivors from the Birkhill zones or fore- 

 runners of the Wenlock-Ludlow fauna. Of the latter, Retio- 

 lites Geinitzianus is very rare, while varieties of 3L priodon 

 are common. 



The zone is typified by the Lower Gala series of South 

 Scotland and the Crossopodia beds of Girvan. It is recog- 

 nizable in Ireland in the shales of Tieveshilly, in Wales 

 in the Tarannon shales of Conway, and in the Lake Dis- 

 trict in the Knock beds. It has been recognized by Dr. 

 Tornquist in Dalarne ; its fossils have been detected by Mr. 

 Linnarsson at Motala in Ostrogothia and elsewhere. It seems 

 to be present also in Thuringia and Bohemia. 



16. Zone of Cyrtograptus Graya?, Lapw. — The upper divi- 

 sion of the Gala group is marked off from the lower division 



