770 ME. F. E. C. REED ON THE LOWER PALEOZOIC [IToV. 1 899, 



graphical provinces and the extension and distrihution of the seas 

 and lands of this period. On the strength of the evidence afforded by 

 the trilobites, Freeh ^ distinguished four marine provinces in Lower 

 and Middle Ordovician times : the British Isles lay in the North 

 Atlantic province, and Scandinavia and Russia in the Baltic province. 

 But of the twenty genera of trilobites which he quotes as peculiar 

 to the latter province, five have long been known from the British 

 Isles, another is not peculiar to the province, another is very rare 

 and found only in Russia, seven others belong to beds lower than 

 any that we are comparing, and another to a much higher horizon. 

 Marr^ believed that the large AsaijJii of the Orthoceras-Yime^tonQ 

 of Sweden did not reach Britain till Lower Bala times, and the 

 Cystideans and Phacopes of the subgenus Chasmops not till the 

 Middle Bala was being deposited. 



It seems, however, that the connexion between the Baltic and 

 Irish areas was closer and somewhat earlier, though in what manner 

 this happened is obscure. The differences in the Baltic and Irish 

 faunas appear to be only such as the distance and probable diversity 

 of local conditions and sedimentation would lead us to expect. A 

 suggestion of the propinquity of the British contemporary facies i& 

 afforded by the occurrence of certain typical British species {Caly- 

 mene duplicata, BelJeropJion perturbatus, etc.) in the higher beds, 

 which shows the gradual loss of Baltic characters and the influx of 

 British forms. The immigration into England of the Cystideans 

 and of the forerunners of the Middle Bala Ghasm.opes may, therefore, 

 have come as much from Ireland as from their headquarters in the 

 Baltic area. 



"We may conclude that during the accumulation of the greater 

 part of the Tramore Limestones the physical and biological conditions 

 in Wales and England did not allow of the spread of their peculiar 

 fauna. But from the time of the deposition of the Dicranograptus- 

 shales the conditions continuously approximated. 



Volcanic activity in County Waterford is seen to have commenced 

 about the period of the accumulation of the Dicranogy'aptus-s\i2XQS' 

 near Tramore, and possibly earlier at Eaheen, where also it con- 

 tinued till after the Orthis argentea-hcds, had been deposited. In 

 the Haverfordwest area volcanic rocks of this age have not been 

 described, but farther west and north in the St. David's and 

 Fishguard districts Dr. Hicks ^ and the present writer * have recorded 

 felsitic lavas and tuffs of Lower, Middle, and Upper Llandeilo age. 



YII. Conclusion. 



The facts above recorded show that the bedded Ordovician rocks 

 of the Waterford coast represent mainly the Llandeilo (Lo\>'er Bala) 

 of England and Wales, but are of special interest because they 



1 ' Leth. Geoga.' pt. i, vol. ii (1897) pp. 88 & 89. 

 ^ Quart. Journ. Geol. Soe. vol. xxxviii (1882) p. 313. 

 3 Ibid. vol. xxsi (1875) p. 167. 

 * Ibid. vol. li (1895) p. 149. 



