170 TWENTIETH REPORT ON THE STATE CABINET. 



I. NATURE AND FORM OF GRAPT0LITE8. 



The name Gra'ptolithus^ originally proposed by Linn^us in the first 

 edition of his "Systema Naturae " (1736), was applied by him to objects 

 of entirely different character from those now known as graptolites, and 

 included fucoidal and other markings of the rock surfaces, dendrites and 

 ruin-marble. 



In the twelfth edition of his Systema (1767), Linn^us included under 

 this generic form several species, only one of which, the G. scalaris, cited 

 from his Scanian Travels, is a true graptolite according to the modern 

 restriction of the generic term. The figure of this species has been several 

 times reproduced by authors ; and very recently, Mr. Garrutiiers, in the 

 Intellectual Observer, has published afac-simile of the original, which 

 I have copied, as well as the translation of Linn^us's description : 



Fig. 1. 



Fac-simileofthe original figure of Graptolithus scalaris. From Skanska Resa, -p. 147 



** Petrefaction of graptolites of a curious kind, found in a slab of slate that had 

 "been broken to pieces; the black characters of which, upon the gray stone, 

 "resembled a line such as might be printed by a coin on its edge, and often ter- 

 ' " minate in spiral ends." 



In this case the spiral ends can have had no connection with the linear 

 fossil figured, but belong to a very distinct species, perhaps to G. convolu- 

 tus of HisiNGER, (PL 35, Sup. fig. 7), or to a similar form. To all 

 persons acquainted with these fossils, the figure of Linn^us represents a 

 graptolite so preserved as to show the cell-apertures directed, partially at 

 least, towards the upper margin; but there has been a difference of opinion 

 among naturalists as to whether it belongs to a species with a single series 

 of cells {Monograptus) , or to one with a double series {Diplograptus)^ but 

 imbedded in such a manner as to show a single series, which would accord 

 with the description of Linn^us, while at the same time the oblique 

 direction of the cell margins (serratures) is more in accordance with a 

 graptolite having a single series of cells ; but if the upper line, limiting 

 the linear figure, be a part of the fossil, it could not have belonged to the 

 latter group. The fact that it is wider than ordinary forms of MoTwgraptus 

 would not, in my opinion, be a strong argument against its belonging to 

 that group ; for at that period, figures of fossils were not always drawn in 

 their true proportions. I have, however, been inclined to believe the 



