HISTORY OF RESEARCH. ciii 



the two regions as respects the thickness, lithology, and palaeontological features 

 of the formations present. 



,g 82 In this year also Tullberg brought out the first part 



TuUberrj, of his great work on the " Skanes Graptoliter." In this part 



" Skaues Graptoliter," of his paper Tullberg divided the whole of the Cambrian 



' Sver. G-eol. Uuders.,' ar ,j Silurian Beds of Scania into successive zones, the 



majority being characterised by distinctive Graptolites. 



The zoning of the strata containing Graptolites is even more detailed than 

 that by Lap worth in his Moffat paper, and the result of Tullberg' s work not 

 only added to the proof of the value and utility of Graptolites as zone indices, 

 and as a means of correlating synchronous deposits in countries geographically 

 distant, but pointed the way to a closely detailed correlation of the British and 

 Scandinavian deposits. 



1883 In the second part of this work, published the following 



Tullberg, year, Tullberg dealt with the classification of the Graptolites 



" Skaues Graptoliter," in general, and the various species found in the Gyrtogra/ptus 

 ' Sver. Geol. Unders.,' an j Qardiola shales in particular. 



Classification. — A modification of Lapworth's classification 

 is suggested. Nine families are recognised. Six of these — Dictyograptidie, 

 Dichograptida3, Nemagraptida3, Monoprionida3, Mono-diprionidie, and Diprionidie 

 — are grouped together under the Class Monophyontes ; one — Heteroprionidaj 

 (including the single genus Dimorphograptus) — under the Class Mono-Amphi- 

 phyontes ; and two — the Glossograptida) and Retiolitidae — under the Class 

 Amphiphyontes. 



Under the family Dichograptidae Tullberg includes not only the true Dicho- 

 graptids, but also Pleurograptus, Cladograptus, and Phyllograptus. The family 

 Retiolitida3 is left unchanged, and contains Trigonograptus and Glathrograptus, in 

 addition to Betiolites and a new genus Stomatograptus. 



The genus Monograptus the author divides into six groups, according to the 

 general form of the polypary and the shape of the thecse, and for these he pro- 

 poses names — i. e. (1) Leptopodes (M. Nilssoni, etc.), (2) Orthopodes (M. Hisingeri), 

 (3) Helicopodes {M. convolutus, etc.), (4) Opisopodes (If. lobifer, etc.), (5) Kamto- 

 podes {M. testis, etc.), (G) Prosopodes (M. colouits, etc.). These groups, it will be 

 seen, correspond fairly closely with those suggested by Lapworth. (' Scottish 

 Monograptidse,' 1870.) 



Description of Species. — A large part of this paper is devoted to the descrip- 

 tion of the Scaniau species, many of which are new. These are admirably figured 

 in two plates, and include : 



Leptopodes. — Monograptus Nilssoni. 



Orthopodes. — M. Hisingeri, M. vomerinus, M. personatus, M. Linnarssoni, 

 M. spinulosus, M. speciosus. 



