Vol. 51.] ANNIVEESAEY ADDKESS OP THE PEESIDENT. lxXV 



But numerous as are these additions to our knowledge of the 

 trilobites of Wales, they only represent a part of Dr. Hicks's 

 discoveries, many of which were announced by Salter ; the most 

 important being that of the finding of a large Paradoxides at St. 

 David's, 1 proving the existence of a Middle Cambrian or i Paradoxides- 

 zone,' co-extensive with the vast area over which these early rocks 

 have been observed, and occupying a persistent horizon throughout 

 Europe and America. 



A brief reference must here be made to the papers published by 

 that excellent geologist and naturalist, the late Thomas Belt, F.G.S., 

 in 1867 and 1868, on new trilobites from the Upper Cambrian 

 rocks of North Wales, and on the Lingula Flags or Ffestiniog 

 group of the Dolgelly District, 2 with figures and descriptions of 

 four species of Olenus (non Gonocoryphe) and four species of Agnostus 

 from Dolgelly. 



In 1888 I was so fortunate as to be able to record the first 

 discovery of trilobites (Conocoryphe viola) in the Longmynd Group, 

 Penrhyn quarries, Bethesda, near Bangor, in North Wales. 3 



The remarkable fauna of the Olenellus or Lowest Cambrian 

 zone, originally discovered in America by Dr. Emmons in 1844, 

 was first recognized in Europe by tbe late Dr. Linnarsson in 1871, 

 in the basal zones of the Cambrian near Lake Miosen in Norway, 

 but its typical genus Olenellus was then referred by him to the 

 allied but more recent genus Paradoxides. This reference was 

 corrected by Prof. Brogger in 1875 ; and the various brilliant papers 

 on the Primordial formations by this author have given the Olenellus- 

 fauna a marked and peculiar interest. In 1882 Linnarsson next 

 made known the existence of the Olenellus-fauna in Scania, at the 

 base of the Swedish Cambrian. In 1886 the same fauna was 

 detected by Mickwitz in the Lower Cambrian of Russia (Esthonia), 

 and this Russian fauna was figured and described in detail by 

 Dr. F. Schmidt, of St. Petersburg. In 1887 Dr. Holm reported 

 the existence of the Olenellus-isbuna in the Cambrian of Lapland, 

 where it was first detected by Morstell in 1885. Thus the 

 existence of this remarkable fossil group, the oldest well-marked 

 fauna recognized by geologists in the Lower Cambrian, had already 

 been demonstrated, in 1888, in three main regions, namely : — 

 (1) in the region of the Rocky Mountains ; (2) in the region of North- 



1 Quart. Journ. Geol. Soc. vol. xix. (1863) p. 274. 



2 Geol. Mag. 1867, p. 294, pi. xii. pp. 493 & 536; & ibid. 1868, p. 5, pi. ii. 



3 Quart. Journ. Geol. Soc. vol. xliv. (1888) pi. iv. pp. 74-78. 



