452 



SCIENCE. 



[N. S. Vol. I. No. 17. 



THE PROTOLENUS FAUNA* 



The above article will be one of especial 

 interest to students of the early Paleozoic 

 faunas, since it describes one of the oldest 

 known. 



From time to time during the last thirtj^ 

 or forty years discoveries of fossils have 

 been made in the Cambrian rocks of east- 

 ern Canada. Those of the St. Lawrence 

 valley and northern Newfoundland were by 

 Billings referred to the ' Lower Potsdam,' 

 but at a later date, together with others 

 found in that valley and in southern New- 

 foundland, they have been more specially 

 correlated with the Olenellus Fauna by C. 

 D. Walcott and others. 



Other fossils found in the lower part of 

 the Cambrian rocks in New Brunswick be- 

 low the Paradoxides bed were naturally at 

 first thought to be also of this fauna, but, as 

 win be seen by considerations advanced fur- 

 ther on, it does not now seem possible so to 

 establish the relationship. 



The discoveries in New Brunswick have 

 from time to time been reported in articles 

 pubUshed by G. F. Matthew in the Transac- 

 tions of the Eoyal Society of Canada, but 

 such important additions were disclosed 

 through the collections made by W. D. 

 Matthew in 1892 and 1893, and by him in 

 conjunction with G. van Ingen for Columbia 

 College, New York, in 1894, that a special 

 article on this, the Protolenus fauna, has 

 been written. From this article the follow- 

 ing abstract has been made of the character 

 of the fauna, and the conclusions arrived at 

 from its study. 



The fauna consists of Foraminifera, 

 Sponges, Molluscs and Crustaceans. All the 

 Foraminifera described are referred to the 

 genera Orhulina and Globigerina; the 

 sponges include Protospongia and others. 

 The molluscs are mostly hyalithoid shells 



^Abstract of a paper commumoated to the New 

 York Academy of Sciences by G. F. Matthew, of St. 

 John, N. B. 



of the genera Orthotheca, HijoKthu:< and Dip- 

 lotheea. A remarkable mollusc having a 

 helicoid shell and supposed to be a Hete- 

 ropod, enables me to establish a new 

 genus. The Crustaceans are chieflj' of two 

 gTOups, Ostracoda and Trilobita, of which 

 the former are remarkable for the large 

 number of genera and species, as compared 

 with the trilobites; two predominant and 

 characteristic genera are Hipponieharion and 

 Beyrichona. All the trilobites are of genera 

 peculiar to this fauna, except Ellipsocephaliis, 

 which, although one of the dominating 

 tj'pes, also occurs in the Paradoxides beds of 

 Europe. The most characteristic genus or 

 trilobites is Protolenus, which is abundantly 

 present in the typical beds. 



The following are some of the salient 

 characters of the fauna as at present known. 

 All the trilobites have continuous eyelobes. This 

 is a decidedly primitive character, and its 

 value in tlus respect is shown by the genus 

 Paradoxides of the overlying fauna, which 

 began with small species having such eye- 

 lobes, and culminated in the large forms of 

 the upper Paradoxides beds in which the 

 eye-lobe was considerably shortened. Tliis 

 shortening of the eyelobe was carried still 

 further in the Oleni of the Upper Cambrian, 

 dwarfed forms, with a general similarity to 

 the Paradoxides, in which the eyelobe is al- 

 most on a line with the front of the gla- 

 bella. 



The important family of Ptychoparidw is ab- 

 sent. This family did not have continuous 

 eyelobes, for in the young, when this pro- 

 jecting fold first shows itself, it is short and 

 at the lateral margin of the head-shield. 

 No trilobite with such an ej^elobe has been 

 found in this fauna . The Ptj'choparidae had 

 about a dozen species in the Olenellus 

 Fauna, and became quite common in that 

 with Paradoxides, and continued to abound 

 throughout the Cambrian period. 



The genus Conocoryphe is absent. This is 

 specially a type of the Lower Paradoxides 



