J^^' THE STORY OF OLENELLUS. 341 



asaphoides, though it is not referred to by him ; and this species seems 

 to have remained as an Olenus until Ford investigated it in 1871 (7, 

 p. 33, and 10, p. 257). Hall, in establishing Barrandia, insisted upon 

 the form of the glabella, of nearly equal width throughout, and upon 

 the narrow elongated pygidium, and commented on the difficulty of 

 determining the facial sutures. Two years later (6) he found that the 

 name Barrandia was pre-occupied, and reverted to what had been, 

 indeed, his first conception, Olenellus. 



Here, then, we have, in 1862, two well described species referred 

 to the genus Olenelliis ; what was known as to their horizon ? It was 

 generally believed that the beds of Georgia in Vermont, with pre- 

 sumably corresponding strata on the Belle Isle Straits in Newfound- 

 land, were above the horizons containing Paradoxides, and were 

 referable alike to some part of the Potsdam series. The Georgia 

 beds thus remained as Upper or Middle Cambrian until 1888, and 

 the palaeontological history of Olenelltis is in consequence full of an 

 unconscious humour. Hall (5, p. 115) prophetically remarked that 

 "these forms" — O. thompsoni and vennontana — "will be found to 

 mark an important horizon in our geological series," but this was 

 on account of their association " with other forms that indicate the 

 last appearance and final dying out of the types of that ancient crus- 

 tacean fauna which marked, so far as we now know, the dawn of 

 life upon our planet." 



Mr. S. W. Ford (7) gave Olenellns additional interest by his 

 researches among the rocks of New York State, and Brogger (8) 

 observed of the Scandinavian Paradoxides kjerrdji that it seemed 

 ** significantly related to the American Cambrian species P. thomp- 

 soni" — the ty^\c3.\ Olenelltis of Hall. This apparently simple remark 

 was the foundation, seventeen years ago, of the present high cult of 

 Olenellus ; it was taken up by Linnarsson (9), who emphasised the diffi- 

 culty of seeing facial sutures in P. kjendfi ; and finally by Holm (13), 

 who removed this species to Olenellus. 



Meanwhile, Ford and Walcott in America fell into a trap that 

 nature had provided for them, or rather remained in it unsuspectingly. 

 The former (10, P..256), treating of the old Olenellus asaphoides of Kmmons, 

 observed that it " may be safely regarded as higher in grade than any 

 known form of Paradoxides whatsoever," and he preferred to keep it 

 generically distinct from Paradoxides kjertd/i, which he looked on as its 

 probable ancestor. His paper is eminently unassuming and fair- 

 minded in tone ; it leads from the small to the great, from the con- 

 crete to the abstract, from embryo-trilobites to the principles of 

 descent ; and it might be urged that here indeed we have zoological 

 considerations confirming the work of the field-surveyor. Those who 

 would absorb palaeontology into zoology, instead of regarding it as a 

 mutually helpful meeting-ground, might feel that William Smith's 

 methods, based on laborious outdoor observation, were destined to 

 find a formidable rival in the established principles of embryology. 



