lvi BRITISH GRAPTOLITES. 



tliat the Graptolites, occurring in great shoals in muddy deposits, probably of 



a deep sea, often unaccompanied by other fossils, and tranquilly laid down on the 



soft carbonaceous floor, would be less likely to be broken up than most fossils." 



He also asserts that Biplograpsus " could never have consisted of two single 



Graptolites, the line of junction being quite soldered up," and he refers to such 



forms as I), ramosus in support of his opinion. He points out that in the genus 



Bidymograpsus the " radix " is sometimes " lengthened out into a long acute point, 



and the branches reflexed," from which it appears that he did not accept Hall's 



assertion that 1). caduceus (Salter) was really a Tetragraptus. 



In a review of Hall's Memoir on the " Graptolites of the 



r . .' Quebec Group," Geinitz criticises Hall's generic list, and 



" Bemerkuno-en iiber points out that there must be four distinct genera included in 



Hall's ' Graptolites of Hall's single genus Grraptolithus, viz. Monograptus, Bidij- 



the Quebec Group,'" mograptus, Tetragraptus and Bichograptus. He considers his 



<Neues Jahrb. f. Min.' 0WR ciadograpsus to be identical with Hall's Dicmnographis, 



but he accepts Hall's genera Phyllograptus and Betiograptus. He again emphasises 



the close relationship of the genera Monograptus and Bastrites, and suggests a name, 



Birastrites, for those Bastrites-like forms having apparently two rows of thecge, to 



which genus he thinks Thamnogr aphis and Buthograptus might also possibly belong. 



He considers that Otdhamia is an alga, but on the other hand he argues strongly in 



favour of Nereograptus being a true Graptolite. He proposes the new generic 



name of Stephanograptus for Hall's species Gr. gracilis, which, however, Hall 



himself had already acknowledged as probably identical with Emmon's Nema- 



graptus (elegans). 



A general paper on Graptolites was published by Carruthers 



' in 1807 in the pages of a scientific magazine known as the 



1( ~ , ,., ',-, . 'Intellectual Observer.' In this he discusses their structure, 

 " Graptolites : their 



Structure and systematic position, and classification. He divides them into 



Systematic Position," four sections — 



' Intell. Observer,' Section I. — " Species with a single series of cells," 



xi (4) and xi (5) including— 1. Bastrites, 2. Graptolithus, 3. Oyrtograpsus, 



4. Bidymograpsus (including Tetragrapsus and Bicellograpsus), 



5. Bichograpsus, 6. Ciadograpsus, 7. Bendrograptus. 



Section II. — " Species with two series of cells." 8. Biplograpsus, 9. Climaco- 

 graptiis, L0. Betiolites. 



Section III. — " Species with single and double series of cells on different parts 

 of the same polypary." 11. Bicranograptus. 



Section IV. — " Species with four series of cells." 12. Phyllograptus. 

 He figures a large number of previously named species, viz.: (1) Gr. priodon, 

 (2) Gr. convolutus, (3) Gr.Boemeri, (4) Gr. SedgiuicHi, (5) Gr.Halll; (G) Bastrites 

 Linnsei, (7) B. capillaris ; (8) Biplog. pristis, (S)) J), tricomis, (10) B. cometa, 



