clii BRITISH GRAPTOLITES. 



1903 The General Section of this Third Part of the British 



Elles and Wood, Monograph continues the History of Research from 1851 to 



" Monograph of British 18G5 ; and the Descriptive Section is devoted to the British 



Graptolites," pt. 3. forms of the family of the Leptograptidae. Four British 



a aeon ogiap ma genera — namely, Leptograptus, Pleurograptus, Amphigravtus, 



Society, 1903. n , T /rt . , . 



and JS emagraptus (Usenograptus) — are recognised, embracing 



eleven species with several varieties. Four of the species are given as new, viz. 



Leptograptus latus, L. sacendens, L. validus (Lapw. MS.), L. grandis (Lapw. MS.). 



In this, as in other parts of the work, the detailed descriptions are preceded 



by a summary of the general characteristics of the family or group under notice. 



1904. A list of the Graptolites discovered by Dr. Bliicher 



Noel, M. G., (1898) and the author (1898—1015) in the pebbles of the 



"Faune des Lydiennes Conglomerates of the ' Gres des Vosges ' of the higher parts 



, ~ e t, j ' of the basin of the Meuse and the Moselle. Sixteen forms 



Comptes Kendus, 



Acad Sciences ' are noted, ranging from Llandovery to Lower Ludlow 



June 13, 1904. inclusive. 



The author summarises the results of her personal studies 



ll/l/'T. m 



Elles G L m e ^ e ^ an< ^ m *- ne laboratory of the Vertical Distribution 



" Some G-raptolite of the recognisable species of Graptolites occurring in 



Zones in the Arenig Sedgwick's " Arenig " Series of his type area and their 



Eocks of Wales," equivalents in other parts of Wales. The rock-successions 



and Graptolite-sequences, as developed in the Arenig Dis- 

 vol. l, pp. 199-211. . . . . 



trict, in Caernarvon, in the Lleyn Peninsula, at St. David s, 



Abereiddy, Whitesand Bay, and other areas in South Wales, are described. These 

 are correlated with the corresponding successions in Shropshire, the Lake District, 

 and Scania. She concludes that three successive Graptolite Zones are distinguish- 

 able in these British Arenig strata, namely, the Zones of (1) Didymograptus extensvs, 

 Hall; (2) Didymo. hirundo, Salter; and (3) Didymo. bifidus, Hall. The oldest of these 

 zones follows in order of time the Dichograptus Beds of the Lake District, whilst 

 the newest graduates upwards into the sub-formation usually termed the Lower 

 Llandeilo, which is characterised by the presence of Didymograptus Murchisoni. The 

 ' Murchisoni Zone' and the underlying c Bifidus Zone' are both marked by the domi- 

 nance of "tuning-fork" Graptolites, and constitute the Llanvirn Series of Dr. Hicks. 

 1904. In this Fourth Part of the British Monograph the 



Elles and Wood, Historical Section is carried on from 18G5 to 1871. The 



onogiap i Descriptive Section deals with the British forms assigned to 



Graptolites,' pt. 4. l ° 



' Palseontographical thc famil J of the Dicranograptidae. Of these only two genera 



Society,' 1904. are recognised, Dicellograptus, Hopkinson, and Dicranograptus, 



Hall. Thirteen British species are assigned to the former genus and ten to the latter. 



The species described as new are Dicellograptus angulatus, Dicranograptus 



brevicaulis, D. celticus, D. cyathiformis, and IK tardiusculus (Lapw. MS.). 



