Art. II. — Victorian Graptolites. 

 Pakt I. 

 (a) Ordovician from Matlock. 



{/>) DiCTYOXEMA MACGILLIVRAYI, noni. UlUt. 



By T. S. Hall, M.A., 



Demonstrator and Assistant Lecturer in Biology in the 

 University of Melbourne. 



[Eead 13th May, 1897.] 



(n) Ordoviciax from Matlock. 



The small collection of graptolites, which is dealt with in the 

 present communication, was made by Mr. E. 0. Thiele during 

 the Christmas vacation, and was kindly placed in my hands for 

 examination through the agency of Mr. G. B. Pritchard. 



The fossils occur in a black, earthy slate in which cleavage is 

 but slightly developed at a very small angle to the bedding plane. 

 They are preserved in a silvery white mineral, and though they 

 thus stand out with remarkable distinctness on the dark back- 

 ground, yet the details of their structure are in most cases 

 entirely wanting, so that specific determinations are not possible, 

 except in the case of one species. 



The commonest forms are clearly referable to the genus 

 Dicellograptus. These occur in great profusion, being fairly 

 matted together on some of the slabs. In no instance are the 

 hydi'othecse shown with sufficient clearness to enable their form 

 to be fully made out, or for counting. One or two examples have 

 the habit and size of Dicellograptus 7)iorrisu, Hopk., approaching 

 more nearly to Hopkinson's figure^ than to that given by 

 Lapworth." The sicula is clearly shown, and the lateral spines 

 can be made out in some of the specimens. What is another 



1 Geol. Majf. viii., 1871, pi. i., f. 2a. 



■^ Pioc. Belfast Nat. Field Club, 1876-7, Apijendix, pi. vii., f. 0. 



