ANNIVERSARY ADDRESS OP THE PRESIDENT. 



tracks {Chondrites) and burrows (Arenicolites) being all that has re- 

 warded patient research ; but below the primordial Menevian, as 

 we have seen, in the promontory of St. David's, there exist greenish, 

 grey, and red flaggy or shaly sandstones, with species of Lingulella 

 differing from the typical L. Bavisii of succeeding age. In the 

 yellow, grey, and purple sandstones and flags we have the first 

 known Trilobites ; and these are of gigantic size — the two genera 

 Plutonia and Paradoxides, with Conocoryplie, demanding from us 

 the belief that they were by no means the first of Cambria's Crus- 

 tacea. 



The earlier highly metamorphosed rocks below the Caerfai group 

 and the Pfotfom'«-sandstones in all probability contained the pro- 

 genitors of these early giants ; nowhere else in the British islands, 

 Europe, or America have species been found of such high antiquity. 

 To the untiring energy of Dr. Hicks we owe the discovery of these 

 rocks and the description of the species contained in them. 



The Menevian of the St.-David's area rests upon and passes 

 insensibly down into the fossiliferous Harlech and Bangor rocks, 

 which contain an earlier fauna, which is not at all represented in 

 North Wales, either at Harlech or Bangor. Only one of the five 

 species of the great Paradoxides found in the pre-Menevian and 

 Menevian beds of South Wales is known in North Wales. The 

 long-known and solitary specimen called P. Forehharnmeri, from 

 an unknown locality, is now determined to be P. Hicksii, which 

 occurs sparingly in the Menevian beds on the Camlan river north 

 of Dolgelly, but more abundantly with its two congeners, P. aurora 

 and P. Davidis, in South Wales, the fourth species, P. ' jBarfcnessii, 

 characterizing only the Harlech group at St. David's *. Associated 

 with these large Menevian Paradoxides, other forms, equally sig- 

 nificant, occur, viz. Holoceplialina injlata, Hicks, H. primordialis, 

 Salt., and Caransia menevensis, Hicks ; and they range no higher, 

 being distinctively typical or characteristic species of this horizon. 



Two species of Anopolenus {A. Henrici, Salt., and A. irnpar, Hicks) 

 are common to the two areas, the former occurring at Khaidr-ddu 

 valley, Tyddyngwladis, near Dolgelly, the latter at the Maentwrog 

 Waterfall. 



No less than 6 species of the genns Conocoryplie occur in the 

 Menevian group : 3 characterize the St.-David's, and 2 the North- 

 Wales beds ; and 1 species, 0. apphmata, is common to both 

 areas. Conocoryphe liumerosa, Salt., C. bufo, Hicks, C. solvensis, St. 

 David's only ; C. coronata, Barr., C. Homfrayi, Salt., North Wales, 

 Maentwrog ; C. applanata uniting the two areas. Erinnys venu- 

 losa. Salt., and Arionellus longiceplialus, Hicks, are both found in 

 the Waterfall-valley at Maentwrog, and the latter also at St. David's. 

 I draw attention to this group of Crustacea because they are strati- 

 graphically important, and constitute by far the most characteristic 



* Dr. Hicks lias added another species from the Trelewr beds below the 

 Menevian, P. solvensis, associated with Conocoryphe solvensis and the so-called 

 Eophyton. 



vol. xxxvii. q 



