The Graptolites of Lancefidd Beds. IT-i 



Comparing the measurements of Hall's figures in Grap. 

 Quebec group, with Moberg's description we get the following 

 (in mn>.) 



C. rigidus. 



Hall l(oVin-) 3-8 5-10 



Moberg Branches twice the size of those of C. tenellus. 



C. tenellus. 



Moberg 2 4 



One peculiarity which is rather striking is the occurrence of 

 specimens which are so delicate that they are mere phantoms, 

 though associated with others which are well developed. At 

 times a specimen svill be fairly broad and distinct at the base 

 and will fade away gradually towards the distal extremity of 

 the branches, so that even with a lens one cannot be certain 

 where the end is. In these examples, as in fact is usually the 

 case, the thecae are embedded and no sicula is visible. Whether 

 this tenuity is real, and due to an under-development of chitin, 

 or whether again it is due to maceration are questions not easy 

 of solution. 



One specimen showed primary branches 1-2 ram. long; second- 

 ary 5, 5, 4, 4 mm. long; tertiary 6, 8, 75, 75, 7'5 mm.; diameter 

 of the primary branches 0*5 mm., while the distal ends are so 

 tine as to be scarcely visible. Usually however it is specimens 

 of var. tenellus with secondaries from 2-3 mm. and tertiaries 

 from 3-5 mm. long which are thus preserved. 



Both varieties are fairly common and frequently preserved on 

 the same slab. 



Phyllograptus, J. Hall, 1857. 



Phyllograptus ? sp. 



(PL XVIII., Fig. 26). 



I have seen a single specimen which I think is referable to 

 this genus. It is partly covered and not in a good state of 

 preservation, so that nothing but the outline can be made out. 

 The fragment is 25 mm. long and the uncovered part is about 4 

 or 5 mm. broad. Thecae 10 or 11 in 10 mm., apertural margin 



