TRANSACTIONS OF THE SECTIONS. 63 



therefore, did Sir W. Ai-mstrong revive attention to this important national sub- 

 ject at the Newcastle Meeting of the British Association; -whilst in this com- 

 munication I have simply endeavoured to indicate that the public are not to be- 

 lieve in the almost boundless range and contents of our coal-fields which some 

 persons woidd assign to them. 



On some Fossils from the Graptolitic Shales of Dumfnesshire. 

 By Hekkt AiLEYUE Nicholson, B.Sc. 



The upper Llandeilo rocks of the south of Scotland have long been known to yield 

 graptolites in great profusion, few other forms of animal life having been recognized 

 as occurring in them. Having had this summer an opportunity of examining the 

 graptolitic shales of Gai-ple Linn, near Mollat, I was struclc with the occurrence 

 in them of munerous bodies, difl'ering from the graptolites in form, though resem- 

 bling them in texture. These bodies present themselves as glistening pyritous 

 stains, scattered in considerable numbers among the graptolites upon the surface of 

 the shale. In their most perfect condition they appear to be bell-shaped bodies, 

 which average three-tenths of an inch in length and two-tenths in breadth, and 

 are provided at one extremity with a prominent spine or niucro, the other termi- 

 nating in a nearly straight, or gently curved margin. 



When compressed from above downwards, a. condition in which they often 

 occm-, they appear as oval or rounded patches, frequently very definite in their 

 outhne, and presenting somewhere within their margin an elevated point, which 

 is surrounded by several concentric ridges, disposed with more or less regularity. 

 The elevated point marks the position of the mucro, and the concentric rings are 

 merely due to vertical compression. When in this compressed condition, these 

 bodies somewhat resemble orbicular Erachiopods in appearance. 



The textm-e of these bodies appears to have been corneous, like that of the 

 graptolites ; but they show no traces of structure beyond the presence of the mucro, 

 from which, in some well-preserved specimens, a filiform border is prolonged for 

 a greater or less distance along the free margui. The mucro appears to have con- 

 stituted their most solid portion, projecting as a marked elevation when obtained 

 in relief, and leaving an evident hoUow in the cast. 



In most cases these bodies are free and independent, but they occasionally occur 

 in such close juxtaposition with the stipe of a graptolite as to justify the belief that 

 the connexion is organic, and not merely accidental. I have not observed this 

 except in Graptolites Seclt/wickii, the form in which this might most reasonably be 

 expected, as the cellules are separated from one another by a conspicuous interval 

 till close to their bases. In this case the origin of the body appears to have been 

 from the common canal or cosnosarc. In one specimen the mucro has been pre- 

 served, and seems to have been situated at the free extremity, and therefore to have 

 been a point of dehiscence ratlier than one of attachment. 



The occurrence of these bodies in shales, crowded with gi'aptolites and grapto- 

 litic germs, and their close connexion in some cases with the gi-aptolites them- 

 selves, would seem to warrant the conclusion that they are " gonophores," or 

 " ovarian vesicles," at first attached to the parent stem, but finally becoming free- 

 swimming zooids. Bodies somewhat similar to these have been described by Pro- 

 fessor James Hall as occurring in connexion with the stipe of Grtqitolites Whit- 

 fddi, a diprionidian form, and these are regarded by him as true reproductive 

 cells. 



If this conjecture as to the natiu'e of these curious bodies (to which the term 

 " grapto-gonophores " might be applied) be correct, then the Graptolitida v.^ould 

 have to be finally referred to the Hydrozoa, and would find their nearest living 

 analogues in the Sertularid(e, from which, however, they would always be sepa- 

 rated by characters sufficiently distinctive. 



The facts that no traces have been preserved of any central axis within these 

 bodies, and that they are not as yet known to occur in other localities where 

 gi-aptolites abound, would to a certa'in extent militate against this hvpothesis; but 

 the first may be due to the soft nature of such an axis, and the second is probably 

 referable to the attention of geologists not having been dii-ected to theii- existence. 



