HISTORY OF RKSMAIM'II. 



clxix 



1912. 



Ruedema/nn, U., 



" Lower Siluric Shales 



of the Mohawk Valley," 



' New York State 



Museum Bull.,' clxii, 



pp. 1-151. 



In this paper the author gives a detailed description of the 

 local succession, lithology, and fauna of the " Utica Slate " and 

 associated sub-formations outcropping in the broad Shale Belt, 

 extending from Albany north-westwards up the valley of the 

 Upper Hudson River to Saratoga and Glenfalls, and westwards 

 up the valley of the Mohawk to Littlefalls and Utica. The 

 memoir, which is illustrated by several good plates and by local lists of the Graptolites, 

 etc., collected in situ, goes far to satisfy a long-felt want in respect to the vexed question 

 of the relations of the so-called Utica Slate in its typical localities to the neighbouring 

 sub-formations, ranging from the Trenton on the one hand to the Loraine on the other. 

 Among the Graptolites cited in the four successive local groups recognised by 

 the author, the following forms are given as new : Dictyonema multiramosum, 

 Dicranograptus Nicholsoni (Hopkinson) var. parvulus, Diplograptus (Mesograptus) 

 Mohawkensis, D. (Amplexograptus) macer. 



The example of D. Nicholsoni figured and described (Fig. 17, p. 79) is especially 

 interesting, each of its branches showing a virgula-like axis prolonged distally as a 

 naked rod or fibre well beyond the theca-bearing parts of the branch. 



This Ninth Part of the British Monograph is wholly 

 descriptive. Diagnoses and figures of some fifty-three British 

 species of Monograptidas are given, among which are many 

 forms not previously recorded from British strata. Four 

 species are noted as new, namely, Monograptus remotus, M. 

 undulates, M. Knockensis, M. delicatulus. 



A detailed discussion, mainly from the palaeontological 

 point of view, of the evidences relating to the probable local 

 positions of the North American (United States and Canada) 

 stratigraphical horizon answering to that usually accepted in 

 Britain and Europe as marking the upper limits of the Bala 

 and the lower limits of the Llandovery. The bearing of the 

 Graptolite species upon the subject is carefully noted, and 

 the discovery of typical Birkhill Graptolites in the United States (Arkansas) is 

 for the first time made known. 1 



A well-illustrated memoir on the sequence and fossils of 

 the Swedish Graptolite-bearing strata which follow at once 

 upon the "Did i/niograptus geminus strata," and answer more or 

 less to the British Llandeilo Flags and Upper Llandeilo. The 

 series is divided by the author into four successive zones, namely, 

 the zones of (1) Glossograptus Hincksii ; (2) Climacograptus 

 piitillits; (3) Nemagraptus gracilis; and (4) a zone in which 



1 Compare also Ulrieh's "Revision of the Paleozoic Systems," 'Bull. Geol. Soc. of America,' 

 vol. xxii, 1911, pp. 481-680; aud Ulrich and C. Schuchert, "Palaeozoic Seas aud Barriers in Eastern 

 North America," 'New York State Museum Bull.,' 1902, lii, pp. 633-663. 



1912. 



Elles and Wood, 



" Monograph of British 



Graptolites," pt. 2, 



Pala?ontographical 



Society, 1912. 



1913. 



Ulrich, E. 0., 



" The Ordovician- 



Silurian Boundary," 



' Compte-Rendu 



Congrcs Gcologique 



International, Canada 



(Toronto),' 1913, 



pp. 593-669. 



1913. 



Hadding, A., 



" Undre Dicellograp- 



tuskiffern i Skane, etc.,' 



' Lund's Universitets 



o p 



Arskrift, vol. 9, no. 15 

 pp. 1-39, pis. hi, viii. 



